I 100% agree with the principle, but (regrettably) in practice you can't do this in a lot of places where the community is critical (which isn't a bad thing by itself) but doesn't call out/downvote/moderate bad criticism (which is bad).

I can't count the number of times on HN that I've seen responses to posts that took advantage of the poster not writing defensively to emotionally attack them in ways that absolutely break the HN guidelines, and weren't flagged or downvoted. And on other sites, like Reddit, it's just the norm.

The defensive writing will continue until morals improve.