We can’t deport them because leftists would have a hissy fit the likes of which we’ve never seen.
What could be done is to codify (legislative statute) to deny them any current or future public support system benefits like Social Security, WICs, SNAP, TANF, Section 8, etc.
IOW, take away the allure of being here and having easy access to leftist largess.
We have to deport them. Seriously, as many as 60 million or more presently in the US. Leaving them just makes permanent the damage being done. There are millions here without papers, or that have been told to leave. No one is hunting them down. Now, over the years, including Trump, we’ve got 10s of millions given papers and years out dates. We are told that 99% will be found ineligible to stay but what does that mean after years?