The reason nobody uses public transit in America is it's always packed with transients or dangerous people. I took public transit all the time living in Melbourne since it was clean and silent nearly 98% of the time. Same in the Netherlands.
A lot of homeless aren't "transients." They aren't just passing through.
If we had excellent public transit to make it easier for homeless people to travel at will, maybe they would be. And maybe their lives would be overall better and they would get less open hatred for being poor and unhoused in a world making it increasingly challenging to get housing for far too many people.