There are arguments that neither party wants to stop the flow of illegal immigration. One profits from cheap labor and the other from future voting demographics. Are both true, neither, or some?
The answer is a blatantly obvious in your face nothing could be more apparent NO.
If they wanted to stop it they would. They don't.
As far as the reasons you give that is a big fat negative.
It has nothing to do with parties or votes or cheap labor. Most don't vote and most work for very small businesses anyway so that whole theory is a complete falsehood.
The elections are rigged anyway and it doesn't matter what party holds what position because both are owned by the same people.
Just like in Europe, well its even worse in Europe, the owners of the world want mass immigration in specific places because it is in their best longterm interests.