There's been a Republican talking point of "real" America (the part that votes for them; ostensibly rural and southern) having a certain set of values. This is just Trump taking the logical next step.
This is going to hurt his election outcome - who knows how heavily, but it could be significant. I'm curious if he'll double down or back off now.
He will double back off. Liberals are out to get him amd Mexican activists are liberals. How was he to know there was an evil liberal racist and a Latino legal organization doing fine work with the same name.