I think their only issue is the unlimited flow of cheap (illegal) labor.
That is a big part of it for sure, but take it a step further: socialize the cost of business while privatizing the profits. A fascist's dream.
They fund the campaigns of RINOs and RATs: their agenda is much, much broader than AMNESTY. For instance, they want to regulate and tax their competition out of existence. That’s one of the reasons why the US Tax Code is the most complicated in the world. And it took 30 years for an American car maker to score #1 in the JD Powers Initial Quality Survey.