Race and difference - how to talk to toddler

My daughter (just turned 3) is white, but our extended family who we see weekly if not daily is very racially diverse. Sometimes she points out that her baby cousin (who she is absolutely obsessed with) is light brown and that her uncle is dark brown and she is light/white. I’ve never discouraged her from talking about these differences because I don’t want her to grow up thinking that there’s anything wrong with diversity and especially nothing wrong with talking about diversity. But then yesterday at the snowball stand, she pointed at a black family and loudly yelled to them/me “mommy those people are brown! And we’re not. Were white.” My sister (who is white and married to a man who is black) immediately swoops in and starts lecturing my kid about how “it’s okay for people to look different and there’s nothing wrong with that” etc etc in a hushed and embarrassed voice. While understandable, my sister’s response made me even more uncomfortable than my daughter’s loud comments because I know my daughter sees absolutely nothing wrong with people looking different and sees no shame in talking about that, which is why she said what she said. So, how can I continue to encourage my daughter that difference is wonderful and talking about diversity is wonderful while also teaching her to be socially appropriate? via /r/Parenting http://bit.ly/2Y3x9x2