Yet an All Lives Matter movement was created by white assholes to oppose the important and meaningful #BlackLivesMatter movement. In saying that "all lives matter," you take the racial issues out of... a racial issue. It diminishes the message that black lives should matter more than they do.
In the video below from SRP TV a white dude tells you all you need to know about white privilege.
So let's recognize that white people have held unfair advantages throughout Western history, and still reap many of those benefits today. If you're white, good for you, but do your best to support other races that don't share those same advantages.