Woah, reading what you wrote in that paragraph shows that he really was abusing his powers. Changing people's names to hurtful words? I don't think that's what a GM should be doing to his/her co-workers.
Also, looking at the screen shots that you have, it seems like he was insulting you quite a lot.
The thing that's getting me is that, I don't understand why he can't just leave you alone when you said you don't need help.
I understand that you're an Intern and that a GM of a higher rank needs to look after you, but if you don't need help, I think he should only be there to look over you, but not help unless you ask for it.