It really depends on who you ask. Overall among the general population, probably Vanilish. The meme of "literally just ice cream" stuck for a while and earned it a good number of detractors. But if you asked the competitive playerbase, the answer would be totally different - probably Landorus like others have said (althougj I haven't paid any attention to that scene in a while). Ironically, among the "casual yet still dedicated" fanbase, I'm actually gonna say Charizard gets both the most love and the most hate. I definitely see a lot of anger directed toward it, mostly for getting shilled so much.
Ultimately though, I don't really think any Pokemon gets *that* much directed hatred. The vast majority of less-than-beloved Pokemon are just sort of ignored, like our buddy
>>40517617, for instance. I think it's because there are so many Pokemon that it's easy to straight up forget the ones you don't care for.
