That's a seriously tough skin you have. I am sorry to hear that the comic artist was a complete dick, as artists I personally feel we should be supporting each other and helping build up one another, and never tear each other down. Critiques are one thing, but blatant hate is unnecessary. The fact that you never gave up, even through all his hate storms, truly shows your character and conviction.
For my comic here on Tapastic, I haven't gotten hate yet but I'm waiting and prepared for it. I know there are things in my story some people definitely WILL NOT like, but it's my story, my world and I do what I want with it. If they don't like it, they can go make their own story with their own set of rules or they can see themselves out of my comic maturely :')
For my first comic Moonlit Dawn: A Mythical Tale, it was originally a webcomic (but it got published so I had to discontinue the webcomic routine for it) I got some hate for it. I had people compare it to the webcomic Off-White and some of them thought I was "stealing" material from said webcomic. I ALWAYS replied to these haters calmly, telling them the only thing the 2 comics have in similarities is that they both have main wolf characters. Other than that, story, characters, lore, and art style are NOTHING alike. Suffice to say, these haters never replied to me.....cowards lmao. Or I've had people comment "Oh another wolf comic, just what we need." To which I replied, true there are a lot of wolf comics but hardly any of them see it through to the end since artists give up around 10ish pages. And that would me being like "Oh another human comic, just what we need" LOL XD