Safety nets have a moral hazard of course. Nothing is perfect. People do fall through the cracks, others take excessive risks and some even game the system (risking being caught and put in jail).
But on net (no pun intended) welfare has reduced poverty. Consider limited liability companies and corporations. They can afford to go bankrupt and starve of resources. The free market discipline can apply to them. But when it comes to living beings such as humans, we need to mitigate the loss.
Imagine a world where people are conditioned to believe that they can't make a very bad mistake even if they want to. Objectively they should be able to make this mistake, but if we allow them to, who is at fault? Is it the person who allowed them to make the mistake? I don't think so.
Same idea for libertarians. If we all knew we were going to be in the battle pit, we'd all done hardened armour, but we mostly think we'll be ok, so we don't.