I'd say that making such determinations based on fragmentary information, such as decontextualised headlines, is a better characterisation. Arguments like these (where some people say "it's abuse!" and others say "it's not abuse!", and nobody focuses on how they're not using the same "it") make the lines seem blurred when actually, it's pretty clear-cut most of the time.

Even if you know the lines aren't blurred, if you perceive others acting as though it's up for debate, you're more likely to consider bad-faith appeals to the subjectivity of abuse as perhaps being in good faith. Few among us are philosophers capable of reasoning everything through from first principles, all the time, so these things matter.

Sure, I agree with all that, well-said. “Dickhead, asshole, douchebag, fuckstain” are terms of endearment in some of my social circles. Context matters.

Tone and body language are like 80%+ of in-person, verbal communication.

We need to be very careful to, as I mentioned, not “abuse” the term abuse to the point where it becomes meaningless. If everything is abuse, nothing is abuse, and we need to invent a new term.