That is true. I have met people of various races who grew up in rural areas and we got along fine. Same thing for engineer types to some extent. Culture, background, upbringing mean a lot more than race.
CDSD, your test is sort of weird. I bet most people would give what I would guess to be passing answers. I don't think I have seen any suburbs around Houston that were all white. The closest thing I can think of might be a small area having $10 million plus homes with a lot of old oil money. I only visited one house in that area though.
I wouldn't term myself a racist. I figure I am certainly prejudiced at times over any number of things including race. I think clothes, cleanliness, and attitude would trigger that more often than race. I think the biggest thing I encounter with black people is that some seem to approach you with an angry or distrustful look/tone. I am generally less talkative with anyone I don't know so the combination is doomed.
I just try to smile and say howdy to anyone I meet and that always helps.
As for the OP, congrats to the guy for accomplishing valedictorian. I hope it provides an opportunity for every student at that college to rethink their own attitude about race.