Have you been outside of the US? Coming from Europe, SF is utterly shocking. I've never seen anywhere else like it. Government provides a lot of support for low-income and homeless people in EU.
I walk by the local drug dealers in the Tenderloin every day, and all the clientele I've seen are homeless people.
I lived in the third largest city in Sweden, and when I moved in there were the handful (like, probably less than 5) of homeless beggars that everyone knew. There were probably more homeless but they were sheltered by the state.
But by the time I moved out, in front of every supermarket there was a Romanian beggar with her head down.
I'll agree SF is definitely on a completely different level though. I've never seen anyone defecate in public outside of SF (and yeah I've been to China)
Should be pretty easy to investigate, arrest, deport them and forbid them to come back.