[Rufbdbskrufb473]

I think the main reason isn't the shelter itself, but that being around a large number of fellow homeless people is dangerous because of the rampant mental health issues, drug abuse, and violent crime.

The problem is similar to what happened when low income housing (the "projects") concentrated the poor into economic ghettos.

[bilbo0s]

???

If they're "poor", don't they have to rent or buy low income housing, and so "concentrate into economic ghettos"?

There is no policy concentrating the poor with each other, any more than there is a policy that concentrates the rich with each other. The market makes available different products, and different economic market segments purchase different products. With a policy, or without a policy, the poor will live with the poor.

And form "economic ghettos".