You're not wrong about office politics. You're also not wrong in assuming racism exists in pretty much every office and industry (this can be used to your advantage).
You're dead wrong in assuming it's just black folks who have a hard time climbing the ranks.
Just because the majority of upper management is white doesn't mean the majority of white people have a shot at upper management. Talent, aggressiveness, and social acuity climb the ranks, regardless of race. It's not about tokenism either. Everyone has a stereotype they have to fight, everyone has a culture they have to fit into it. Turn it into a positive instead of complaining about it.
...and while you complain, certain guys are going to be winners no matter what because they get it.
New rule: You can't complain until you've done everything in your power to succeed. Until you've put in 12-14 hour days for weeks on end, until you've broken your body and mind down, until you've failed and failed in order to succeed, you don't have the right to an opinion.
You can keep bringing your negativity (I'm sure you'll call it "realism") around, but I've said what needed saying.