Eh, there were some people that hated him from the moment he was announced because they think he's a D-bag or because they don't like his band. But I think most of the vitriol towards him boiled down to three things: 1. the Joker's overall look in the film, 2. his on-set antics (or "method acting") and 3. his performance. Now, #1 and #2 could have probably been overcome if #3 worked for people. But it didn't. Suicide Squad made a lot of money but it's generally understood to be a bad movie and Leto wasn't one of the elements people liked. Anyway, I agree that he has to go. I know a few people here and there like him and others think he could have been good had the material been better (and I would agree with that sentiment) but the damage is done. Cut bait and move on. Phoenix is likely one and done, but that doesn't mean they can't recast the DCEU Joker and give him a more classic (or at least better) aesthetic.