tf is going on in Japan?

Probably no different than anywhere else, its just because the few crazies that exist slip through the cracks and have an easier time doing something like this in Japan because its just so out of the ordinary/unexpected and they aren't adequately prepared for it. In both cases, the assailants literally walked right up to both Abe and Kishida, and they were never searched, never stopped, etc., security was purely reactive.

I am sure there are plenty of similarly crazy people in the US... But our country is full of guns and our police/security details already expect people to be armed, already expect the crazies coming out of the woodwork, etc., and there is just so much screening and security, that those crazies get caught before ever getting anywhere close.