They’re absolutely right, and you’re wrong. In the moral sense.

You’re treating it as a moral imperative that (to be charitable) all able-bodied adults in a society must be somehow self-supporting, and using that as justification to either browbeat the recipients of minimum-quality-of-life benefits in order to continue receiving them, or to deny such benefits entirely after some point.

Given the relative wealth of our society, it’s immoral to cut off minimum-quality-or-life benefits when doing so would result in people becoming homeless, hungry, or sick. Even from a strictly utilitarian perspective, that will in the end impose higher costs on society than just distributing benefits.

Similarly, if what you actually care about is the cost to society in a utilitarian sense, the cost of the administrative overhead of browbeating benefits recipients and doing the necessary tracking to ensure benefits are cut off when they reach their endpoint and stay that way will be higher than just distributing them.

So what is your actual moral argument? It comes down to “everyone should have to work.” And, well, why? Some people can’t work and I hope you don’t begrudge them being cared for by society. Similarly there are the young and elderly who society should care for, rather than rely just on family to care for. So why is an able-bodied adult different to you?

If the argument is that you have to work so others should too, well, under the proposed scheme you actually don’t! If you want to just hang out all day every day on minimum benefits, I wouldn’t begrudge you that. Sooner or later you’ll probably work anyway just to get more than is possible at the very bottom. Or maybe you’ll create art and contribute to society that way. Or maybe you’d avoid being a drag on a workplace that’d be a bad fit for you, and contribute in that way. Or maybe you’d be able to devote your time to raising a child so they can contribute much better than if you weren’t there because you were working.

A morality that treats work as virtuous for its own sake is too simplistic to survive contact with the real world.