The thing is that blue/green is Deku's color scheme, and his normal outfit is the color of the pants he's wearing right now. (like, if he was wearing his normal hero outfit, he would look as blue as the villain is red) Obviously in this specific scene, this is what he's wearing, but I don't think one can deny the implication that Deku is supposed to be blue, because that is general color.

The artist is not above criticism and that's not what I'm implying. I'm saying that the utter pretension is the problem. Criticism is not objective. It might be true that under a specific academic lense, the ideal color here would be a different one, but it is wrong to say that Horikoshi is plainly incorrect.

Again, it's not just insulting Horikoshi -- it's insulting the entire industry. The guy is literally saying he knows better than everyone in all of JUMP. If the case was as he says, that this background/foreground combination is 100% false and Horikoshi is incorrect here, this would not go down. The volume covers doesn't just go through the artist doing whatever he wants, not even just through his editor, there are entire sales departments that need to approve this.

The idea that this guy knows better than all of those people makes him -- undeniably -- a pretentious prick. It's not name calling so much as it is factual.

Now again I will repeat that I concede that under specific laws of color harmony there might be a more ideal combination that Horikoshi could've gone for, but I don't believe that he should have. I don't think he needs to work on his color choices at all, because he has been consistently choosing beautiful combinations that portray what he wants to portray.

Dismissing his ability is just condescending and incorrect. So I will repeat it: there is no need for Horikoshi to work on his color choices, his covers are completely fine as they are. They are what he wants to portray in his art, and the manga industry is backing up his choices, there is absolutely no reason for him to change.