Poverty isn't culture. But by your takes I'm confident in saying you aren't a cultural expert.
I also call bull on your friend. If he got picked on it was because he was lame. Not educated or successful. Corny and lame black people who would be picked on regardless if they were black or white love to say that instead of admitting they were just geeks. I was a black kid who was in all honors and AP classes and all of that. I was known for being super smart since I was in elementary. I was never picked on for being a nerd. Some white kids in my same classes were. By white kids because they were "nerds."
Its hilarious that one of the most well known tropes, which countless movies, films, tv shows, books, and whatever popular media you want to name is the white kids picking on nerds. When a black kid is picked on for being a nerd racist use is to confirm their biases . When a million things about white nerds or dorks or geeks being bullied are about white kids its just kids being kids.
Inner city and the trailer park are not the same culture, Just the same economic struggle leading to some of the same problems. Culture is music, art, language, traditions. Different things buddy.