Zimmerman was 150% wrong and should have been convicted. He had no reason or right to go and chase someone around for no reason. He killed that boy in cold blood when he fought back. He'll get his one day.
And I don't need to explain anything away with quoting another incident. I'm just stating the obvious that there's more to this than just some beatdown.
So the white bf did something to them or someone else they knew? And it was all planned out?

Let me guess something like, he raped one of their sisters or he scammed their drug money. Then the white guy got off light.

My guess is, since the girl was dressed up, they were partying and one of the black dude got rejected. Maybe her bf told him don't touch my girl with your dirty hands? And he told his friends that this white cracker told him don't touch with your nig hands?

Happens all the time in Germany. Here it's mostly turks, russians or balkan boys.