One of the strong points of the current president is kicking out illegals, so it could be argued that abolishing the ICE would be simply antidemocratic.
Personally I don’t think the president has any strong points other than being a racist, misogenoist, pathological liar, and narcissist.
At a minimum, refer to them as unauthorized immigrants, since that is the distinguishing factor from a public policy perspective.
No more than labelling those who commit crimes as criminals.
Subjects of foreign states — i.e. aliens — who are present illegally are illegal aliens. That's what they are (in addition, of course, to being human beings, with parents and rights and hopes and dreams and all the rest).
Labelling them 'undocumented immigrants' is a bit too cute, since many of them do retain the identifying documentation issued by their states. It's also begging the question of whether they should be immigrating at all.
For myself, I philosophically tend towards completely open borders, but I do wonder about the practical implications, and I dislike the blatant dishonesty & appeals to emotion common on both sides of the issue.
These are people who are inside the US in violation of immigration law.