White people have a long and embarassingly awful track record for violence to non-whites. As one of the earliest explorers of the world, as white explorers "discovered" new places with non-white peoples, thinking themselves superior, fair and just treatment wasn't anything they thought well of.
Today, whites in the US are the majority by just a slim amount, and wont be within our lifetimes. This fact probably weighs heavily on many minds manifesting as a significant amount of animosity which when combined with a situational gripe can quickly become violence.
People have a long track record,people of every color,violence/bigotry/racism is color blind.
Tell it to Columbus. White subjugation of non-whites because the non-whites were "savages" relative to European peoples.
People who subjugate other people are ALWAYS stronger and smarter than the people they subjugated.
No one stopped the blacks in Africa or the redskins in America from getting on their boats, sail to Europe and subjugate whites, except their own inherent stupidity which survived and defied centuries of attempts by white people to have them educated.
A chip on the shoulder is a wonderful thing in today's politically correct society.