That's messed up. Deporting somebody who has been in the country since they were a kid to a place they might not know anything about seems pretty cruel, regardless of your criminal history. After 20 years, you should be dealt with like any other citizen (however shitty that might be in the US).

On the other hand, I could see temporary deportation (with means to get back after some weeks / months) as an interesting punishment -> maybe realizing that not breaking the laws and working a shit job in the US beats scavenging for water in Africa..

Anyways, I have no advice for you, no idea what I would do in your position but I wish you luck.. hope you can get into UK or somewhere and start fresh.