What is text evedence that racism it the theme?

From the text:

I didn’t need ROTC. But I did it, and I did it good, because my dad was pretty much making me. He's one of those dudes who feels like there's no better opportunity for a black boy in this country than to join the army. That's literally how he always put it. Word for word.

“Why does it automatically gotta be Rashad's fault? Why do people think he was on drugs? That dude doesn’t do drugs. He's ROTC, man. His dad would kick his ass. You do drugs, asshole.”
“Just a puff here and there, man, come on. I don’t do drugs."
"I’ve seen you smoking a blunt. Metcalf sold you that shit. Metcalf––a white dude, by the way. Man, that shit could have been laced with crack, or fucking Drano. You don’t know what you talkin’ ‘bout.”

Now I was thinking about how, if I wanted to, I could walk away and not think about Rashad, in a way that English or Shannon or Tooms or any of the guys at school who were not white could not. Even if they didn't know Rashad, even if for some reason, they hated Rashad, they couldn’t just
ignore what happened to him; they couldn't walk away. They were probably afraid, too. Afraid of people like Paul. Afraid of cops in general. Hell, they were probably afraid of people like me. I didn’t blame them. I'd be afraid too, even if I was a frigging house like Tooms. But I didn't have to be because my shield was that I was white. It didn't matter that I knew Paul. I could be all the way across the country in California and I'd still be white, cops and everyone else would still see me as just a “regular kid,” an “All-American” boy. “Regular.” “All American.” White. Fuck.

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