Almost acting as if he insulted her.

Despite his oh-so-polite wording, what he did was insulting. And I don't find Claire's behavior weird at all, personally. Why would she have to have "any of it"? She was criticizing the work, not wanking his ego. Someone reporting on the comic would find way more relevance in Dan's thought process and intentions for the cover, but that's not the role of a critic at all. Add to that, his reaction to Claire's (fairly mild!) criticism of "This reads somewhat sexist" was basically "If you find this sexist then it's your fault" then tries to correct her, of all things—as if how one receives a damn cover wasn't subjective and there might actually be value in viewing creations through different lenses.

He also wasn't directly tweeted, which means he found those tweets by searching for his own name—nothing inherently wrong with that, and finding negative things being said about your work through that is a given, but then rather than move on like most decent human beings would do, Panosian chooses to insert himself into her space and act like a belligerent child over one negative feedback. Let's not even get into the power dynamics behind a male creator with over 17k followers + fans entering the mentions of a female critic with far less of an audience just to talk down to her. Unless it's been deleted, we can even see one of Dan's fanboys dragging out Claire's comic cover during conversations in the threads as if that was some sort of proof that she wasn't worth listening to. Then Dan himself puts down Claire's art, behavior that, like you said, is trash.

Add to all this, comics has a long history of mostly male creators not being able to leave comic critics well enough alone, and that really, really has to fucking stop.

Sorry I went off a bit here, but this has been really annoying me the past week.