Should the homeless have pets?

I am of two minds on this. While I don't think it's the best thing for the dog, I can understand if a person had a dog before becoming homeless and then could not separate from it. I know I would have a very hard time doing so.

Also, I wonder if some of these cases might be where a homeless person finds a stray. We know that in many cities there are dogs that have gotten loose from their homes or have been dumped by owners who don't care for them anymore. I wonder if these homeless pairs bond and sort of help each other survive. They become a back because they both have nowhere to go.