Here's the thing, most artists go through creative jealousy. And that's fine. Seeing some popular artwork and thinking "hu, that's not that good" is a pretty normal thing to think, but I'd say with the thought of "I'm better than that!" you're definitely crossing over into jealousy. Not of the other artists abilities but the attention the person is getting for their artwork.
I have been there a million times. As an artist I am totally biased about my own work. Even the pics I don't think are that great... I poured hours into them! Why isn't no one rolling out the red carpet for me, I created ART! Why does that person over there get all the likes, gggrrrrrrrr! So I personally am not really ashamed to admit my jealousy. Sometimes the "this is unfair response" also gets triggered depending on how famous the artist is. Like, we all know how terrible Rob Liefelds anatomy is and he still earned millions of dollar, heck yeah I'm gonna tear into his art! He didn't deserve all that money and fame anyway!
However me being jealous does have nothing to do with my criticism itself. If I liked the artwork, I wouldn't have had any criticism in the first place. There are tons of famous artists I follow that where I just don't have criticism. So assuming I'd criticize a work just because I was jealous? No, that's not how it works. Rob Liefelds anatomy is shitty, doesn't matter if I would like to be as famous as him or not Easy target, but you get the idea.
Fans get defensive. Accusing you of jealousy is basically plugging their ears and going "lalalalala can't hear you!" so they don't have to engage with the criticism. I mean it's the internet, most people don't give good criticism and most people don't want to hear it, at least in a typical comment section