What are you trying to suggest? That people only work to avoid homelessness? That homeless people deserve to be homeless? That providing homes to the homeless would cause people to stop being productive members of society?
There are 300M Americans. If 999/1,000 people say "hey, free housing is great, but I'm going to keep working" and 1/1,000 people say "hey, free housing! I can just kick back", we now have an extra 300,000 people who are on the dole (almost DOUBLE the current number of homeless).