Obvious, it means not someone who is working illegally. It means engaged in what normal people understand as specifically illegal activity, I guess you need me to list some examples, to give you a clue.
gang membership
murdering
raping
child molesting
robbery
theft
burglary
drug relate offenses
If you think about it very carefully, it may come to you what is meant. Your comment:
“That’s like saying show all the people in prison that haven’t been convicted of a crime should be set free.”
Has no relevance to the discussion.
Ah so coming to this country illegally isn’t illegal. Very interesting. Well if it’s not illegal to come here illegally why are we worried about them?