Why should we help the dregs of society?
Because if we help them, they might stop being dregs and start contributing. Most people want to earn their own way in life, given the chance to do so.
It won't be 100% of them. There will always be people who want to cheat the system for their own personal gain. Such is a fact of life. But if we help all those who don't want to be dregs to start pulling their own weight, society as a whole gets richer, and we can then afford the luxury of supporting the few deadbeats at the bottom.
Most people want to earn their own way in life. If denied all options to do so, they will still want to survive. If the only way open to survival is to cheat the system, that's what they will do. That's where dregs come from.