I also did Little Tokyo which was quite nice compared to the rest of the inner city! It made me jealous we don’t have something similar in Sydney.
Something that surprised me since visiting is when I was looking into videos and content around the LA Metro to see other’s experiences there are always a group of people commenting that it’s statistically safe and nearly always the exact same point that you’re more likely to get into a car accident than be harmed when riding the Metro. But so long as people high on drugs acting violently are a frequent sight I don’t blame anyone for opting to take their car instead even if that means horrific traffic.
It’s a pretty poor reflection on a society where people are pushed down without sufficient support to the point that the level of homelessness and drug addiction is so prevalent and I hope one day that will be dealt with appropriately but in the meantime I also feel for the working class people who may be forced to ride a system full of dangerous individuals due to their inability to drive for whatever reason. If I lived in LA I’d want security staff at every station 24/7 making sure that those entering the platforms are paying a fare and aren’t in a state that’s dangerous to people around them.
Also, if someone is at the point where they are overdosing on the street/in public or acting violently due to drugs they should probably be forced into mandatory rehabilitation to get clean and then supported to re-establish a life afterwards as they’re a danger to everyone around them as they are.
Homelessness in LA is one of those issues that no one really has a good solution for, unfortunately. The current mayor Karen Bass has made homelessness her primary focus and has made great efforts to house people and make resources available to them, but there's a limit to what can be done.
LA's weather is pretty moderate year round, so that makes it a pretty ideal place for the homeless since it's easier to survive outside with or without a tent when there's not a lot of extreme weather. There's also the issue that other cities/states give homeless people free bus rides to Los Angeles to pass the problem onto us and there's not really anything we can do to stop it. The high cost of living in the LA area also increases the chances that someone might become homeless because of financial circumstances. Not enough housing is being developed to match the population growth of the area and the housing that is developed is often luxury apartments that are ultimately left vacant and written off for tax purposes because it's more profitable than creating low income housing.
A lot of the homelessness problem here actually happened when Ronald Reagan was governor and he shut down a bunch of mental hospitals and released a bunch of people with severe mental illness. The mental hospitals he shut down were not great places, in his defense, but the act of just throwing them on the street instead of trying to improve our mental health facilities caused lasting damage that I don't think the state has ever really recovered from.
Sweeping the streets of the homeless is often a losing battle and there's still the issue that you need a place to put them and there are legal limits as to what you can do (you can't usually involuntarily commit them or arrest them unless they've done something extreme enough to warrant it). The most recent strategy has been to go to camps and get them to voluntarily relocate to temporary or permanent housing in hotels and then once the homeless camps are empty prevent them from reforming in the spot and minimize the red tape in the process. They also obviously offer support for looking for jobs, housing, getting mental health, and getting help with addiction, but a lot of it requires making those things appealing to the homeless because legally we can't really do a lot more than that. Being addicted to drugs, being mentally ill, and being homeless/sleeping in public are all legal (and the courts have ruled as such here) and you can't really arrest someone or commit them unless they commit a crime or are enough of a danger to themselves or others.
I think you're right that the Metro system needs better security if they want more people to use it. Personally I'm hopeful that the public transit system in LA will improve after they've finished the high speed rail system that's in the works that will be able to take people between Los Angeles and San Francisco and they'll see increased pressure to make the greater LA area more accessible to people without a car. The public transit system in LA was sabotaged a long time ago by General Motors and some other oil/tire/other related companies that wanted to make us reliant on cars by buying up the public transit system and dismantling it (the movie Who Framed Roger Rabbit actually it about this).
I once went to see the premier of an anime movie alone in downtown Los Angeles late at night and my phone was almost dead when I left the movie and I got kind of lost trying to find my car and I ended up taking a wrong turn and wandering through a homeless encampment. I still found my way back, but it is kind of uncomfortable having to confront the reality that there are a lot of people who live like this and society doesn't really have a solution for them. I think it made me feel more sad than unsafe.