I've always been of the opinion that if you want to control how a piece of land is used, you should buy it. If you want a bunch of indigents living on land that is very in high demand, raise the money, buy the land, and build a homeless shelter there. If you don't think that's a wise use of money (i.e., maybe you would prefer to help 10 times as many poor by using land that is in less demand) then don't contribute to the scarcity of already scarce (and thus expensive) private property.

It's sad that people want to manufacture an outrage over the simple reality that if you live in a place you don't own, and others are willing to pay more than you to live there, you need to find a new place to rent.