DhA, you have to understand that when you attack a poster, especially one people resepct, some people may react by wondering what your credentials are to make such a statement. Honestly, someone who's been here a while and has accumulated 1,400 posts or something like that is in more of a position to make those statements than someone with 200 posts.
Now, that's not to say they have more of a right to say it. You've got the same right to say it. And you make a valid point about people going to the "who the fuck are you" strategy. That's simply why it occurs, though.