Interestingly, during my one bar night out in Seoul on an overnight visit to change visas for Japan, some dude started a fight with someone and tried to grab a knife sitting on a table while being escorted out. The people around me didn't seem particularly horrified by that spectacle though. I lived in Tokyo for 6 years, SF feels fine coming from there.

Was it in Itaewon?

You're probably right. Similarly, the tolerated racism in South Korea would also be terrifying to people here.

American cities are more violent, yes. But it doesn't make a lot of sense to pin that on San Francisco politicians, which usually seems to be the endgame with these warnings about how dangerous it is.

I'd wager this is the case for most American cities if you are coming here from Seoul

100% agree with you. Asian cities feel much much safer. But there is a lot more context and history behind why it is.