Childish logic. You can't find every single illegal immigrant, and even if you could deport all of them (which is not even realistic) many of them would just come back.
YOU DON'T WANT ICE AROUND? HERE'S A GOOD WAY TO GET RID OF THEM; ALLOW THEM TO ARREST AND DEPORT EVERY SINGLE ILLEGAL IN THIS COUNTRY AND DON'T ALLOW THEM TO COME BACK...PROBLEM SOLVED