Tonight I was watching X Factor with my brother. When that little guy was crying my brother said "I bet he is thinking 'I hate black people'" (The remaining contestants are black and the girl that left is his friend)

Then he said that Owen will be a loner in the house they live in now. As though X Factor is the 1950's US bus system.

Now I didn't want to correct him and in the process kill the mood and alienate him but saying that's not on and he doesn't realise. My Mum and Dad are the same. Do you ever experience this? How do you correct people without properly falling out/ creating tension?