That sounds like employee behavior that should've been addressed since yesterday. In no way is that useful "work"
After all, all that matters is productivity, not anything actual useful, and what's more productive than putting out a 4000 word response in under 5 minutes? That used to take actual time and effort!
Now it's up to me to escalate this whole thing, bring it up with my manager during the performance interview cycles, all while this sort of crap is proliferating and spreading around more and more like a cancer.
In my view, what's on the order is deleting their comment and reminding them that they are entirely out of line when they pollute like that. Whether that is a wise thing to do in your situation I don't know.