The larger point is that when you have someone putting themselves in the position of a subject matter expert talking about how things work, how deadly they are, etc. and proposing new, very impactful laws that affect a basic constitutional right then you (well, I) would expect them to know the subject very well and be the expert they claim to be. Calling a magazine a 'clip' is one example of this. Another is when they make blatant and ridiculous claims that are not remotely accurate (such as saying a .223 round from an "assault rifle" is "so much more deadly than any other weapon" when, in fact, it is one of the least effective rounds among all non-rimfire rifles (in some states, a .223 isn't even legal for hunting deer because it is at the very low end for effectively & humanely killing said deer) it shows just how blindly they are pushing their cause and how ill-equipped they are to be taken seriously. So, people who do know how things work and what the facts are picky and tend to criticize those folks because of the importance of the topic.
You can call your outboard a motor all you want if you're just talking about it in general. Because it really doesn't matter beyond semantics. But when you want to curtail peoples' rights you better not be misguided.
Rob