Conflict vs Abuse: Are we blurring the two?

I read an article recently that argued that a lot of people use the language of abuse to talk about conflict, and that that isn't productive. E.g. Your (also adult) sister flakes out on you on your birthday, you tell her that it hurt your feelings and you're kind of mad at her, she accuses you of being emotionally abusive b/c that's a guilt trip. (A recent example from real life that got me reading the article, actually). 

So there does seem to be some truth to this. The more I thought about it, the more there are a lot of things that happen in personal conflicts that are shitty and do show up in "signs your boyfriend is abusive" type lists, like: 

Your coworker gossips about you to someone else, you confront them on it, they tell you you're overreacting and are emotional. Technically, that IS invalidating your feelings and is very shitty and is the sort of thing that shows up in an abusive relationship. But it also sounds pretty typical of what people do. To me, contextually, there's a big difference because: a) that sort of thing is abuse as a pattern, not usually just a one off b) your coworker doesn't really control your life and you're not emotionally dependent on them in any way c) you feel bad at the moment, but the actual damage is pretty minimal. You won't be scarred by this. 

Do you think they sometimes get blurred together? How can we distinguish between the two, especially since there's abuse that CAN be very subtle. Is it a question of power dynamics? Proximity?