(1) First, Le makes the common error of assuming that if someone is an activist and an academic that they are an academic activist; this is not true, and it is in fact entirely possible to maintain a clear distinction between activism as a citizen and activism as an academic. Activism as a citizen is not any different for academics than it is for plumbers and fry cooks. The question at hand is activism specifically as an academic.
(2) Le also drastically exaggerates the centrality of activism to political response:
Rawls puts that every citizen has a duty to correct unjust institutions and activism has historically proven as the best method to achieve that goal (the Vote for Women campaign, the Civil Rights Movement, etc.)....But once the evidence has been gathered and the facts established in accordance with the best available evidence and information one can have (the question of epistemic justification is a different one and deserves a post of its own), it is indeed everyone’s duty to change the unjust social, political and economic arrangements through activism.
This is not at all true. There is a sense in which it is, all other things being equal, one's duty to change social, political, and economic arrangements that are unjust; it is illicit to jump from this to the assumption that it is one's duty to change through activism, which is merely one of a wide range of options available to citizens in different circumstances. Nor is it always or even usually the best for most people in most situations. In practice, our primary duty with respect to injustice in society is to work on improving our own interactions with other people. Activism is not something to which most people have a duty; it is something done (ideally) in service to a community, precisely because most people are not in a position to engage in the kind of activism that is relevant to a specific problem. Activists are facilitators; their purpose as activists is not to act on their own behalf but to help bring options onto the table that are not generally available without someone specifically working to get them on the table.
It's important to avoid activism inflation, which treats everything important as if it were activism. (One gets this in recruiting pamphlets and websites, where, attempting to encourage first steps, it is often said, "Activism is just taking action to achieve social change." This ignores the 'ism' of activism, and in practice they never actually include all the actions people do in fact take to achieve social change -- prayer and being nicer to people, for instance, are pretty much never discussed despite being among the most common actions taken for achieving social change.) This would make 'activism' a largely useless category; everyone would turn out to be an activist already, just by going to vote or donating to a charitable organization. Most of our essential civic work -- and this includes our responses to injustice -- are not activist in nature, but either interpersonal or self-educational, and this is so because these are in fact the fundamental aspects of life as a citizen, and arguably as a human being. Activism is something we develop as a sort of instrument to these actions.
(3) Le likewise fails to recognize the risks of activism. Activism is sometimes quite necessary, but it is always carries at least some risk of being counterproductive. Serious improvement of society requires not just having good intentions; it requires having means that are themselves good and appropriate, and this is harder than it sounds. Activists sometimes put communities into the awkward position of trying to defend excesses; activists embarrassing the people they are supposed to be serving by speaking for them in inappropriate ways is, unfortunately, a common occurrence. Indeed, activists themselves generally recognize that this is inevitable and that you just have to tolerate some of this if you are to accomplish anything at all. Every politically active community has its fringe counterproductive embarrassments who are tolerated because it would be even more counterproductive to try to shake them off, but it's also the case that even sane and experienced activists slip up on a regular basis. Activism regularly deals with slippery and complicated problems, and sometimes you will simply fail to read the situation correctly. There are always risks; activism is not something you can afford to engage in with starry-eyed optimism, as if it were a royal road that gets you to the destination by magic. Activism is difficult; not everyone is well suited for it, and even those who are often fail in pretty serious ways.
Le, in the passage quoted above, gives a few examples of successes of activism in support of the idea that activism is the best way to correct unjust institutions. What he fails to consider is that most activist projects fail. This is common knowledge among serious activists; the most successful always insist that you need to diversify your approaches to addressing problems because you often don't know what will work in a given situation.
(4) But the point at which I am consistently most skeptical of Le's argument is in his characterization of academics. Here are some examples:
The nature of academic research is such that we are often in the position to come across many disturbing facts before the general public is aware of them. The training we receive also enables us to ask difficult questions, the answers to which might not be welcomed by everyone....
It is, therefore, true to put that academics, owing to their special training, have a role to play in establishing the facts....
None of these, I think, are plausible characterizations in general. The training academics receive quite clearly does not usually "enable" us to ask difficult questions relevant to political issues; academics are only rarely better situated than non-academics with regard to "disturbing facts" that are relevant to political activism; and academics are likewise rarely the people establishing the facts most relevant to just society. Academics have a tendency to contribute theory, not activism, and this is for the very obvious reason that academics are usually better equipped for developing theories and hypotheses than for solving social-political problems, which is the sole and total reason for activism. I have noted before that academia tends to teach academics to overestimate the practical significance of purely reputational and symbolic concerns, leading them to try to achieve things by pure reinterpretation. It's notable that of the three activists Le mentions -- Kate Manne, Angela Davis, Martin Luther King, Jr. -- only Manne is actually an activist qua academic, and her primary contribution is a theory. King was a pastor and preacher, and that is where he found the skills to engage in the work he did; Davis learned her activism in the Communist Party, and while she did have a career as an academic, most of her activism occurred well outside her role as an academic, for the obvious reasons that go with being a Communist academic in the United States during the Cold War. (Nor is she a particularly good example of academic activism; she has had a long history of actively supporting some horrendously oppressive regimes on purely ideological grounds.)
(5) There is an ironic unsuitability for academics to address the problem Le thinks especially important:
We live in an unjust world where inequality remains high, especially among Western democracies, the treatment of those less fortunate – refugees, homeless people, benefits claimants – often fails to meet the demand of justice (Professor Philip Alston, the UN special repertoire, for instance, criticises the UK’s treatment of those living in poverty, stating that it has inflicted great misery on the poor).
It is odd to think that academics have a direct role to play in solving a problem constituted by inequality because academia is an inequality-making profession. The whole purpose of the profession is to create haves that are distinguishable from the have-nots, to make a significant difference in outcomes between those who go to college and those who don't, and many colleges are quite clearly supported by states and governments on the assumption that such an investment will at least sometimes yield an advantage over other states and governments, whether directly (e.g., by providing researchers in key areas) or indirectly (e.g., by expanding the potential of the labor force). People who are literally paid to create inequalities are perhaps not the best people to criticize others for a problem rooted in inequality.
Nor do academics themselves have a good track record in treating well the relevant have-nots (those without college educations); and a vast portion of even academic labor (adjuncts) is consistently and increasingly exploited by other academics. It's difficult to see how it's a good idea for academics, who quite clearly can't even keep their own house tidy, to go around pretending that they can, as academics, clean the city.