They never point out the fact that the Mexican ruling class is white.
Discrimination based on skin color is a lot more obvious in Mexico than in the U.S., from what I saw while working there.
And they're not the ones hopping over the border.
"Make Mexico Great Again" is mostly shipping their illiterate, unskilled Mestizos over here so they don't have to deal with them.
You wanna see real racism? Travel to Mexico (or any other Latin American country for that matter).
Old Spanish royalty. Most of Central and South America are still kind of leftover Euro caste systems.
Richard Dana wrote about skin tones in his classic book, Two Years Before the Mast (1840) during his trip to Monterrey, CA. It's an interesting read.