Mexicans and Mexican-Americans are socially conservative - it was just a matter of time before they started asking themselves what exactly they have in common with the Democrat loons. This is a culture that values and respects strength - the likes of Jeb Bush giving them Democrat-lite in Spanish was never going to work. A strong, conservative leader will.
And those living here often realize that the newcomers drive down their wages while competing for resources. Open borders make THEM poorer.