Look, in his defense, the vast majority of his drama was really spurred by Kamui's bullshit.
The "not gonna complain bit" understandably feels scummy, but as a fellow mild autist, I know the thought process behind it. It's usually a genuine sentiment of "this isn't quite what I asked for, but I'm still thankful for free art."
Like, yes, he can be irritating, but he's not going to learn if the only response is gets is "get the fuck out of here". He needs a genuine explanation of what he did wrong, because he genuinely doesn't understand otherwise. It's just something that autistic people struggle with. I used to be pretty much the same way until I had a crash course in human interaction in the form of working retail. It takes time.