This is not merely a hypthetical. Vlad Tepes (Yes, The Impailer ) notoriously invited all his poor to a grand feast, instead to kill them all. (I think he burned them alive.) Usually in feudal and early capitalist societies, it was just enough to deny them basic necessities and let them die off, but this often would lead to an outlaw problem as some of the more able poors would turn to banditry and poaching to live.

In liberal societies, just as we don't outlaw people anymore, there are some known good reasons to support low income, disabled and marginalized groups.

One of them is to cut off or discontinue the outlaw-to-professional-criminal pipeline. People who are forced to work but cannot for some reason will resort to poaching, banditry, fraud or any number of extralegal revenue-enhancement tactics. Criminal syndicates such as the Crips and the Bloods pull their numbers from demographics that are given no other choice by the society they live in.

Another reason the state might support it's low-income demographics is in recognition that capitalist societies teem with social roles and efforts that contribute value to the society without compensation. Parenting is the primary one.

In fact, in the US, as social programs for low-income households have been defunded or rendered inaccessible (such as SNAP and Medicaid), millennials and zoomers are now choosing not to have children, and avoiding romantic relationships, so that the fertility rate is well below the replacement level 2.1 children. We're not just not having kids, we're not having sex.

Also, thanks to deregulation, and the failure of wages to keep up with inflation, a lot of the US is under-compensated. Much of the poor population in the US have jobs, but they're not being paid a living wage. Infamously, Walmart workers still have to rely on SNAP benefits and Medicaid because their wages are not enough to afford a sustainable living. They still count as poor, and would be swept up if ICE were to start going after poor Americans. And then Walmart would find they have fewer applicants, and might have to offer better wages and benefits. (This happened after the great resignation when workers furloughed during the COVID-19 lockdown found they could monetize their home hobby, or just didn't want their shit job anymore.)

But this isn't to say these uncompensated or under-compensated people are useless or not contributing to society, just that what they do isn't recognized by the system that rewards value with compensation.

Curiously, our political class and our ownership class both imagine they could dispose of the poor without ill effects, even as they directly depend upon those people to parent, to maintain homes, to organize communities and yes, even sometimes to do basic labor. At the same time, they're also the ones screeching about how American women are not having enough (white male) babies.

Just as the US is suffering a shortage of farm hands to harvest crops, thanks to the persecution of immigrant workers, when we deny benefits and services to low-income houses, we'll find that other work we depend on will cease to be done. And that will be accompanied by a new wave of organized crime... or maybe organized resistance against a state that has turned violent against them.