What's the meaning behind "Tio Tacos"?
Tio means uncle in Spanish, so a Tio Taco is the literal equivalent to Uncle Tom. It's the slur invented by chicano activists to libel anybody of Mexican ancestry who didn't agree with their extremist program.
"Tio Taco"
I'm so glad you asked someone old enough to remember! Back in the unlamented late 60's, black Americans who were not filled with hatred for whites, and believed in peaceful dialogue, were denounced by the militants as "Uncle Toms" (from the 1859 abolitionist novel).
During the same period Mexican-Americans who failed to join the militant Chicano movement were denounced as "Tio Taco's", an imperfect rhyme with `Uncle Tom', equally insinuative of subservience to the white majority.