I don't want to get into it toooo much here but he's well-known for centering organizing campaigns around himself and his ego, which includes doing a really, really bad job at actually organizing ALU for a contract and some mild (I'm not sure how to phrase that unproblematically but it's far less bad than most) sexual harassment stuff that I won't repeat exactly but that will probably become more widely known the moment Amazon decides he's a threat to them again. Both are things coming from organizers very close to ALU work.