It’s not ICE’s opinion about who is illegal, it’s congress’s. Didn’t they create the immigration laws that are on the books? I can never understand why people seem to blame the enforcement agencies for the laws they are enforcing.

But I agree with the sentiment that they are selecting the easiest targets.

ICE can make them un-illegal by granting them parole, without further action from congress. AFAIK they can even do it unilaterally, though congress could choose to check them later.