The appropriate reaction if anyone sees a problematic post is to report it using the forum functionality. You are also welcome to call out unacceptable behaviour in thread, but constructively and calmly, and by focusing on the content of what has been said rather than the individual. A heated response will just escalate and prolong the problem, which is why we ask folk to avoid that.

"You may call it 'nonsense' if you like, but I've heard nonsense, compared with which that would be as sensible as a dictionary!"