I'm asking this ? on this site 'cause I am more comfortable here-and much of this site is about prejudice

I sometimes feel that America--the US is so racially charged it's like a bomb ready to go off and blow your great nation apart. It was (and still very much is) black vs white..and now everyone vs mexican. Before that it was Native Americans against Europeans. What I really don't understand is how the people that came over from Europe and just took over the land can now say that it isn't right for someone else to do the same? It was never right for anybody to do that..but surely we have learned to be tolerant of others..or have we? I don't mean to sound like I don't think the US is a great place...but I really worry about the rampant racism that is so obvious on these sites. Is that the way it is in reality? Or am I just picking up all this racial rhetoric because of the sites that I am on? Racist remarks are everywhere on here. Why? Aren't most of us beyond that now? Please this is a serious question. I am not trying to insult anyone.