Secondly, there is a difference in context, timing and tone in an article like this. Here, a PhD supervisor is speaking generally about the sorts of errors his students tend to make.

In your situation, you were "attacking" a single person publicly. If you had had the social grace to make your comments privately and in person (rather than in a chatroom) they probably would have been better received.

If your takeaway from this post is just to "ignore the haters" then I'm afraid you're missing out on some real opportunity for self-improvement.