Oh, that's easy.
I mean, I am a certified 'Noob' after all.
Now, I feel that the question you are asking is confused.
A Noob making fun of another Noob, is like, friendly rivalry.
A Noob making fun of a 'Newb', on the other hand, well.
That's just what Noobs do; be annoying.
It's nothing serious. Everyone is potential victim.
Also, when a Noob makes fun of someone who is a Newb, it amplifies the fact that, they, themselves, are a Noob, which is why they are doing it in the first place.
Being a Noob is a fine-art.
Being a Newb is easy. All you have to do is be new to something.
I happen to be ranked number 3 on the World Wide Noob Scoreboard.