The problem is that eventually you need walls or forced relocation. We have evidence that people are already willing to live in SF with no shelter, and without changing fundamental ways America works, you can’t force them to leave and not come back (maybe a city can get a restraining order protecting itself? No idea).
Force cannot be used but offers of food, shelter, and care elsewhere can and must be offered. In general, only the very rich can afford to live in the most central, desirable locations because the costs of everything are so damn high. It's only fair that most people who aren't insanely rich (like me) should find somewhere they can afford to live or where society can afford to help them. Trying to linger in SF Presidio or Manhattan is well above almost everyone's means.
