So then how are these people slaves if they could just not voluntarily choose to illegally enter a systemically racist country where people of color are hunted by cops like dogs and treated as subhuman trash by all white people?

I never said any of those things, just that legal immigration barely exists.

I was responding to someone saying illegal immigrants in the US are slaves because they immigrated illegally instead of not doing that.

I disagree with the degree severity of the OP’s statement. But US foreign policy coupled with shifts in climate (political and meteorological?) have made large parts of Central America pretty unlivable. To the extent the we are responsible for the state of affairs in Central America, we should be taking in refuges and economic migrants.