I’ve seen that myself; they can be as ignorant as gringos that all Spanish speakers should resemble Aztecs. When a white person speaks Spanish, many of them are amazed (and confused).
Oh yeah. They’re taken back when gringos start speaking Spanish. If ever I’m around them and they’re speaking it I wait until the right moment to butt in and man are they shocked and red faced because they know I’ve cold busted them. For the record Mexicans and Puerto Ricans speak HORRIBLE Spanish. I had a year of Spanish a long time ago during my freshman year in Essex Catholic High School and my teacher was a Spanish woman from Spain who had a doctorate in about ten different languages.