This is evil, treasonous and immoral, but, it is the least nefarious reason for the invasion.
I agree that it may be the least nefarious but it may be easier to understand for the population at large.
Not a single Democrat votes with American citizens. Between the images of thousands at the border, the obvious crime victims of illegals and the simple explanation that Democrats are diluting the value of the vote for most American citizens, a commercial could be cut and run over and over again.