I'm gonna bold a part of this so that I don't get misconstrued as saying that I think this is okay.
Most unhoused people at this point are literally incapable of making the decision to seek help. They've scooped up a lot of the people who were cognizant enough to make the decision not to be homeless. If you are not mentally ill and you're struggling there's lots of groups out there to help you. What's left on the street are mentally ill and/or drugged out people who are incapable of deciding anything for themselves. Someone has to step in to help them, but we don't want to. It costs too much or it's a civil rights problem so we just won't. We'll point at Reagan defunding shit even though its been 40 years since then. What excuse do we have for not fixing it? And we've decided as a society that homeless people are a class of people below every other class or race of people.
This killer committed manslaughter but he's never getting convicted of anything. Anyone who rides public transportation in a major American city knows that it's not safe. We decided that it is okay for people to be terrorized on public transportation. If I was a woman or if I was LGBT I would never get on a fucking train in NYC or LA, because something bad is overwhelmingly likely to happen to you. When did we decide that was fine? The inevitable end result is either that some homeless person pulls out a strap (yes, some of them are strapped) and shoots up an entire train car, or that someone kills a homeless person who was hounding people for money and/or terrorizing them.
This was inevitably going to happen. When a society decides that it's okay to let this many people be homeless and struggling we have completely lost our way. The killer should be in jail, but it's not happening. You can pull almost anyone off a random train car to ask them if they've seen some fucked up shit on the subway and they'll tell you they have. That doesn't mean someone should die for it, but this is all our faults. This also isn't the only time this will happen.
The homeless situation here completely fucks with my own ideas of civil liberties but I prefer not to bring it up. When the things that homeless people do infringe on other people's civil rights, when do you step in? A woman can't ride the Metro in LA without being harassed, without someone pulling out their dick, threaten to rape them, kill them, all that kind of shit. We'd rather just pretend it's not happening. Also, when it comes to the Metro, when most people see shit on there they don't report it because why would you get a cop involved, they either won't do anything or they'll overreact.