Anti-Semitism has been exploding in Western Europe since around 2005. There’s been one violent attack after another, with things getting markedly worse in the past 5 years. It seems quite myopic to analyze the Pittsburgh attack outside of this larger trajectory and instead use it to repeat, for the bisillionth time, that Trump sucks.
P.S. And I just found an article on Spiked saying the same thing but better: “It looks very much as though your concern is less with the slaughter of Jews than with the question of who is slaughtering them, and whether or not the murderer’s identity lends itself to the propagation of your own narrow party-political worldview. In this case, that Trump is a bad person. The wickedness of an anti-Semitic act is judged according to the act’s political usefulness: how awful that is.”