Illegal immigration, at least what we're seeing NOW, is NOT about labor. It isn't even about votes, not directly anyway.
It is about human trafficking. Whether it is cartels buying politicians or the so-called elite and powerful that benefit from it themselves, those in Washington don't want to do anything about it because doing something will harm them financially or otherwise. It is also about creating a permanent welfare state.
This is NOT a Republican problem except for the fact that Republicans aren't saying anything about it.
Illegal immigration MAY have been a labor related issue, to some extent, 20+ years ago, but not now. Calling it one now is useful idiot territory (or trying to deflect the issue from the real problems).