It feels to me like the author misses the point somewhat. I think the conclusion is correct, that is, contentious terms should be avoided. However, it seems to

It feels to me like the author misses the point somewhat. I think the conclusion is correct, that is, contentious terms should be avoided. However, it seems to him contentious means divisive, rather than terms whose definitions are contended. The terms referred to certainly are divisive, but for good reason: they seem to have many interpretations and, from what I can tell, primarily facilitate equivocation. As in, the point of these contentious terms is not to guide everyone to a shared understanding, but to trick people into agreement to justify some action.