I would agree with this.
Most of the people that I know that dislike a race as a group have not actually had any bad dealings with them. It's just that they grew up with their parents, friends, etc. saying things that stuck with them their whole lives. And when you ask their reasoning behind their ideas, it's always something like 'well, that's what I heard', or 'I always believed....'
Until people are better educated and start to have ideas and identities for themselves, stuff like this is always going to happen. Hell, there are still people driving around with bumper stickers in my town that says "The South may have surrendered, but I sure as s*** didn't!"