One I've seen a lot recently is the same kind of problem with consequentialism. Consequentialism has a well-established philosophical meaning. In the words of the SEP article:
Consequentialism, as its name suggests, is the view that normative properties depend only on consequences.
Or in the IEP article:
Consequentialism is the view that morality is all about producing the right kinds of overall consequences.
Even Wikipedia has the right idea:
Consequentialism is the class of normative ethical theories holding that the consequences of one's conduct are the ultimate basis for any judgment about the rightness of that conduct.
(Of the three, the SEP is the most accurate, because it recognizes the existence of consequentialist approaches to things other than morality. But this is just a matter of how restricted our focus is rather than any fundamental difference.) You'll notice that in each case the issue is taken to the limit: "only" in SEP, "all about" in IEP, "the ultimate basis" in Wikipedia. Thus nothing can be consequentialist unless it is in a context in which the entire approach to the area relies on consequences 'only' or as the whole point or as 'the ultimate basis', however you prefer to phrase it.
There are a lot of amateur consequentialists on the internet, however, and they tend to slip up at precisely this point and treat any ethical justification or account in terms of consequences as consequentialist. This hopelessly muddles up every sort of ethical discussion in which the slip is made. Not every appeal to consequences as a moral consideration is consequentialist. If you appeal to consequences in moral reasoning, but what counts as the right kinds of consequences ultimately depends not on the nature of the consequences themselves but their conformity to some moral law or universal set of obligations, you are not a consequentialist but a deontologist. (Kantianism, which a major form of deontology, rejects all appeal to consequences in moral reasoning, but this is not universal among deontologists.) If you appeal to consequences in moral reasoning, but what counts as the important, right, or good consequences depends on how they reflect on, or feed into, character in some way, you are not a consequentialist but a virtue ethicist. To be a consequentialist in a particular area, everything has to trace back to consequences -- if anything essential doesn't, you aren't a consequentialist.
Likewise, the fact that people appeal to consequences in moral reasoning has nothing to do with consequentialism as such. You could make an argument for consequentialism based on how easily people slip into appeals to consequences, but this would be an obviously weak argument without a considerably greater amount plugged into it. But mere appeals to consequences in moral reasoning is not consequentialist; for anything to be consequentialist, they have to be the only admissible appeals in moral reasoning ever -- it all has to come down to consequences directly or indirectly, and nothing else. The mistake of conflating the two things is equivalent to assuming that to be rational we must all be rationalists.
This is all exactly parallel to the fact that mere appeal to rules or moral obligations doesn't make you a deontology. People aren't generally inclined to slide from 'justification based on obligation' to 'therefore deontology', though, and I think it's the -ism mistake that makes the difference. There are other examples besides these of the -ism mistake -- empiricism seems to get a lot of it, too, in which people move freely from 'empirical' to 'empiricist'. It's something that generally needs to be avoided, though, when -ism indicates philosophical positions, systems, or theories.