Even if that's true, the I-know-better, snark-plus-clichés genre is a problem here regardless of how bad an article is. This sort of comment is common on the internet and poisons the environment it's posted to. By practicing it here, you degrade the community and make it less interesting for all of us. That's the real reason not to do it: for much the same reason you don't litter in parks. We want thoughtful conversation here, not acid. Even about bad articles.

Btw that longitudinal Harvard study has been well-known and interesting for long time, despite its flaws. Previous HN threads have discussed it without sinking into snark and I doubt that the community has become smarter since then.