Surely homelessness is, in and of itself, a symptom of a much deeper rot? I'm not trying to excuse the behaviour of these people, but if you feel that society has shat on you, and robbed you of your dignity, might you not want to return the favour? Homelessness is rarely a chosen situation; every homeless person has a story, often a dire set of circumstances that landed them on the streets. It may be personal problems, substance abuse, or mental issues - all things people need help and treatment for. Many of these things are, at the root, down to lacking education or social support structures; symptoms of a society that doesn't care.
Don't get me wrong, the affected businesses are justifiably angry, but their anger is misdirected; sometimes the perpetrators of crime are not the root cause. In small part, maybe they are part of the root cause.