Basketball stan wars are toxic, I think its mainly because basketball has promoted superstars more than other team sports. Its been a marketing trap for the longest time. People hated Peyton, Brady, Richard Sherman, Moss, Baker Mayfield, TO, damn near every mobile QB. But you are correct, it doesn't rise to the toxic level of NBA superstar hate. (Curry, Kyrie, Bron, Kobe, MJ, Dwight, KD, Harden) get more hate that any star QB I can remember. You don't usually hear personal chants in NFL, MLB stadiums directed at individual players like basketball. I'm not saying it never happened in other sports but not nearly as much as NBA.