My cousin's youngest daughter is racist. She loves Barbies so my cousin got her a bunch of them, and she was excited about every single one until she got to the black Barbie. She gave it a disapproving look and then gave it to her sister. After my cousin snuck it in with her other Barbies one day, it disappeared and they don't know where it went.
She is 5.
They have no idea why she is racist, since no one else in the family is.
When I was her age, I was playing My Little Pony with native girls who were a fair bit older than me. Yes, My Little Pony existed then and I played with them.