It's reasonable for people have access to public services. If you turn every public service--sidewalks, parks, libraries, public transit--into something unusable because it's really an ersatz homeless shelter, there's an entirely expected response: people cease to use those services, because they're not really public anymore. And then people either vote to cut funding for those services, or they defund with their feet.

Governments have functions and services beyond homeless services they are obligated to provide. Saying that no public services will be provided until homelessness is solved is not a sustainable approach.