Smoking is binary: you know if you are smoking or not, and other's do too. An 'abusive relationship' is not binary, and is laden with evaluative meaning, subjective, contextual, differing from culture to culture.

Perhaps most importantly such terms are subject to concept creep due to prevalence changes in society. This is not something people put much consideration in to, but the trade-off in educating people (a good thing) is the slow pathologising of every aspect of healthy human relationships. Which, incidentally, is what this article is about.