No, it's not obvious. There are plenty of bigots who maintain their bigotry even whike knowing people their bigoted against.

It's another example of the effect of meeting people from X demographic making you more tolerant of X demographic. It's good to have lots of real and concrete examples of known effects to prove that the effect is indeed real and still applies in the modern day. "Look, it's not just a hypothesis, here is it actually happening! Several examples so you know it's not a fluke! Something recent so you know a culture shift or whatever hasn't neutered it!"

I learned about this effect through reading stuff on the internet when I was young. It might be some other 10-year-old onlooker's first intro to it.