Forgive my ignorance. I did not see them, at first. Now I have but I had to go to your profile, just as you said previously, I believe.
These insulting comments are probably enough evidence: https://steemit.com/cryptocurrency/@coininstant/pxxsr4 and https://steemit.com/cryptocurrency/@themarkymark/pxvzjk. And you even wrote that "He has been banned from most tribes as they don’t want his toxicity in their communities.", so I just assume that there are many more of such unnecessary comments by him out there?
Besides, as far as I know is @gtg a polite Steemian. So I really do not understand why he needs to insult @gtg that excessively.