We had a fareless area in downtown Portland for many years. It was no sketchier than the routes going to the 'burbs, and it wouldn't have made sense as a "makeshift homeless shelter", since the free part was only a few miles. My understanding of why they started charging is that our country suddenly ran itself out of money paying for simultaneous stupid wars and giant tax cuts for wealthy people, and our city couldn't pick up the slack any other way.
You say "homeless people", I say "George Bush", I guess.
You say "homeless people", I say "George Bush", I guess.