I think Uel's revenge makes sense - it's supposed to be purely emotional, not logical. John Wick did similar things and the movies got a lot of praise, no? I think we shouldn't underestimate at what length people can do for revenge.
I don't think Galsh people are viewed as evil by Robart citizens, giving that the latter still welcome the former as customers in the town. It's just that everyone is afraid the magical PETA members might do something funny in the town when Galsh is around, not the Galsh themselves.
Don't get me wrong, i have no problem with revenge for killing a dog, because revenge can come from anything. Even something small like "someone stole my toys when i was a child so i'll revenge against him". I have no problem with revenge because of a dog like John Wick. And i will also have no problem if Uel's action is purely "revenge" (up till the part with his uncle's death i still have no problem, it's still revenge).
The problem is everything else. A guy killed John Wick's dog, so he killed him (and his family in the process but it's because they want to stop John). Uel isn't just revenge, he simply hated humanity to the point
used humanity as food for animals, eating humans and used babies as fuels for Cells. That hate really come out of nowhere, his hatred should only pointed as his uncle. His backstory also showed no part of anyone else aside from his uncle did anything to him (hence why i said Jace have more reasons to hate humanity than Uel). It's almost as silly as some edgy revenge manga MC where he want to destroy humanity because his family killed by a group of bandits.
This is also why i said Odie has better motivation. Odie's character was a prideful a$$hole from the beginning, his action of
becoming Master, destroying Galsh and everything else can also be justified because he just want to prove that he's superior than everyone else. That's not his revenge, his target for revenge is only
Dino (and her friends). To me, that's a consistent character and reasonable revenge. I love Uel, his designs, actions and personalities are super intimidating, even way more than Odie and he also feel like the main villain more. Just his motivation feel lackings and not justified enough.