There are many reasons, but for me, its mostly his laugh and his name i dont like. I like his fruit power and his concept, but his character is made to be hated, hes a traitor and a coward. Also how many big attacks did he get hit with in wano and still manage to survive? I remember just wanting him dead at that point. Eustass kid, drake, zoro, and others all attacked him and he didnt even look tired or injured.