I am sure even the Dems are tearing him down.
I still think the primary motivations is to service the labor unions. The chief purpose of the minimum wage laws and the child labor laws is to knock out cheap, convenient labor mostly from teenagers. Why hire an inexperienced teenager when you can get union labor for the same price.
Now there's a new source of cheap labor that's undercutting the unions. You can't say "Ship them back to Mexico" because it would outrage your base. So you just ensure that it costs as much time and trouble to hire illegals as it does to hire union workers.