There's nothing new about the victimisation of the 'different', the pressure to be normal (whatever that is) - the relative safety as one of the crowd.
Examples go right back through history, often fuelled by fear (not hate) of minority groups. Is it a basic reaction, as with animals attacking one of their own with obvious differences?
It's there in the school playground - be in with the bullies or victims - your choice. Look to your leaders (the staff), which group do they belong to? We can stay on the edges, avoid being violent, look the other way - but are we brave enough to intervene?
Of course, we like to think (in theory) that we're kind, considerate, open-minded, loving and reasonable. What happens when things suddenly get dodgy, out of our control or downright dangerous? We're aware of the threat, our survival instinct kicks in and we're truly frightened? How we react can come as such a shock!
Basically, we're still hunter gatherers, cruel, violent savages, just underneath the surface, after all.