We used to lock up the mentally ill and disabled in state run institutions. They were generally horrible (see One Flew Over the Cuckoo's Nest). Reagan shut them down and homelessness on the streets surged. His government also cut federal assistance to local governments by 60%. The country never tried to find solutions and the issues never got better.

The police in D.C. are not there to fix homelessness or crime. They are there because fascists need brute troops to intimidate the populace and keep people from 'disorderly conduct' like protesting or demanding their rights.