Them: If you are detained by ICE even if you do have __legal status__

You: doesn’t that just prove my point that if you are here __illegally__

They're talking about the now well-established fact that ICE is pursuing people who have legal status in this country and using all sorts of tricks (both legal and illegal) to prevent them from exercising their rights.

Here's one example: https://en.wikipedia.org/wiki/Detention_of_R%C3%BCmeysa_%C3%...