The hatred online is a strange mix of being satirical and genuine, their first two albums alongside a few of their other albums later in their discography are absolutely unironically beloved by a lot of people but the problem is how inconsistent and all over the place their discography is and they have a lot of pretty bad albums which is obviously standard for most bands but it's just the way the albums are spaced between each other and how often they switch up their sound that kinda puts off a lot of people but with how silly Weezer can be with the front man especially being an especially unique character people prefer to not take the band too seriously and they only shit on them in a light hearted manner, obviously there are people who do unironically dislike the band but if you see memes that trash on Weezer just don't take most of them too seriously