I wrote that as food for thought. I guess people don't like to think while they eat but would rather complain that there's a cockroach under the table. Of course African-Americans shouldn't assume that all whites are racist. First of all, there is no proof that they are. Second of all, it would be a crappy way to live, wondering if every white person they came into contact with(especially in a work or police related environment) was out to hurt them economically or physically. However, when we look at the statistics and deal with what we know about the system, we know that racism against minorities is something that many have to deal with in some point in their life. When it's mild, it's just words and discrimination. When it's bad, it could mean not getting that job, not getting promoted or making a lower wage. At it's worse, it could mean jail time or getting shot.
Of course poverty and geographic location will change what kinds of racism one is exposed to as a minority. However, socioeconomic and geographic factors do not explain away or alter the fact that there is racism at hand in our society. If this were the case, then middle class or wealthy African-Americans and other minorities wouldn't be exposed to racism and its effects. There is no evidence supporting such a supposition however.
Go back to the Cheerios commercial video and look at 3:41 where the little African-American girl says that it's not over yet. This is what many white people fail to understand. They think that just because there's a mixed President(yes, he's half African-American) and they see people like Denzel Washington on the big screen and countless pro athletes who are making a lot of money, that there is no reason for people to complain. However, discuss this issue with any minority and you will hear otherwise. I had a friend in high school who was driving his father's BMW in the suburbs at night. He was pulled over by some white cops who asked him if he had a record as they checked him and the car. When he said no, the cop said that they were sure they could make something up to pin on him.
So for being African-American in a nice car in a predominantly white neighborhood, the assumption that he was a young drug dealer or up to no good, not that he had a rich father who let him drive his nice car with his friends. Even Lenny Kravitz got pulled over when walking in Miami because of a depiction of a criminal being black. Sure, he should've had an ID on him, but there is something deeper happening in our country that only a blind man with a blindfold in a pitch black room could miss
http://www.mtv.com/news/articles/1437130/lenny-stopped-by-cops.jhtml
So no matter how rich or famous you become, if you are an African-American, there is still a chance that you will be affected by a system and society that is inherently racist. There is no excuse or amount of reasoning that will change this fact.