I see your point but I take issue with a couple things.
The overall tone of hate and division isn't helpful to having realistic conversation and debate on these issues. It's disappointing coming from someone who nominally wants to change minds.
But more importantly, this argument is extremely Americentric and historically blind. There are places like Ireland that are full of angry white men that have been horribly mistreated long times before African slavery started. Ever wonder where the "Gingers have no soul" meme comes from? And African descendants have plenty of blood in the past too, look up what Shaka Zulu did to Zwide's mother. Does that mean that the sins of the father should be visited on the sons perpetually? I don't think it does for anyone.
I'd like to discuss your theorem: "What is a negative stereotype of an angry white man? There aren't any." I'd just like to point the obvious. They're shallow, closed minded, insular, pedantic, and self-centered. It's the Fox News greatest hits.
You also have a misconception about the term "Social Justice Warrior". You seem to think it's a dig against social justice as a category, when it's not. It's a rejection of the idea that social justice can only be accomplished by war. That it can only be, as you so painfully put it, "a zero-sum game". Why must we crater the beautiful idea that diversity, inclusion, and equality enrich us all? What happened to Dr King and his Dream? Look back at Jesus, Gandi, and MLK. Then, and tell me what has changed more than love and peace. Hate isn't the answer.
This blurb had a defeatist and pandering attitude, full of casual racism and I feel it wouldn't serve to change one mind that didn't already believe your tenant. Your arguments were malformed and your barbs missed the target. But I thank you for sharing your thoughts and hope you don't take my criticism too harshly. I just think race relations are too complicated for either a Tumblr blog or /r/GamerGate. Please respond, I'm very interested in your take on this. ^_^ (also, please excuse any autocorrect shenanigans, this was typed on mobile.)