For many thousands of years, the underlying principle of civilization has been "might makes right". The governments in it codify their laws such that the government itself becomes the regional monopoly on the justified use of force. Within the past few centuries, civilization has slowly been moving towards "the ends justify the means". While that is slightly better, as a fundamental organizing principle of civilization, it is still not ideal, in my opinion.

For now, civilization largely consists of a mutual compact regarding when it is morally acceptable to employ violence. In exchange for obeying the rules, we are promised some of the benefits resulting from collectively standing down from a state of universal hypervigilance.

A hungry and homeless person may perceive that he or she is not getting their fair share of society's mutual benefits. Civilization has not honored its end of the bargain, so they need not honor theirs. There is no moral reason for them to restrain themselves from committing any act considered a crime by civilization. They may still choose to remain within the law, for practical reasons, but it would not be because they are morally obligated to do so. They could rebel at any time. Many do not, and never will.

Consider that if no one ever went outlaw, civilization would have little incentive to give its underclass anything. If you only need a million warm bodies to run the machines, you dump 3 Mcal down the feed chutes every day, and let the rabble argue among themselves over who gets to eat it. If no one is willing to fight the system, everyone is safe to ignore.

Civilization would serve itself best by ensuring that its bounty is distributed evenly enough such that those at the bottom perceive that they would have something significant to lose by rebelling. Though it may also preemptively defend itself against such people by ensuring that they cannot present a significant criminal or military threat if they do turn. You can build shelters and bread lines, or you can build prisons and walls. Not coincidentally, those are the typical strategies of parties considered "left" or "right" politically, worldwide.

If it truly is a last resort, a human with nothing is not ethically restrained in any way from doing anything at all. It might be breaking your car window and stealing something out of your back seat. It might be beating you to death and eating your liver. It might be to give you the sad, puppy-dog eyes, shake some change in a coffee cup, and sing the blues. A civilization that provides no benefits cannot reasonably expect conduct different from the savage, naked savannah-ape in the wild. They don't always kill each other, but they certainly don't worry about laws when they do.