Whats with the amount of racism on 4chan?

I mean I can understand sometimes that there are people that just say racist things without a reason but then this just makes other people follow up in this, I have been on 4chan for about 4 months now, call me a "newfag" or whatever you wish but I'm only here in the board to ask one simple thing, why are there so many people that are racist to blacks, asains, mexicans you name it, its been done, I simply want a normal answer not somthing stupid like "aaaaahh FUCK YO COUCH DIRTY NAAAGGAR!!!" I simply want a reasonably answer, were all human, and most of us have the brains to answer a question like this with reason, and not acting like an idiot, so yeah. I tell you this much now, I honestly hope you guys don't act like this in real life because limmiting yourself to only liking white people really risks a lot of things in life, things that you maybe never new would really change your life in any way before. So yeah I just want a simple reasonable answer to why there is so much racism on this site.

I find that being racist just for the sake of being racist is one of the worst things ever, Why does 4chan keep with this, I mean even if they are all joking maybe some of the biggest 4chaners you will ever hear or see of just happens to be black, I mean do you not think this would afend them? If this was just a single post every, I don't know, lets say 1 hour then I could understand but I mean its used as often as any other 4chan phrase out there, I know that people might say that it's pointless to fight over the internet and that it would be simply impossible to end the amount of racism on 4chan but maybe even if I could get a few people to stop acting like this I would be happy enough, but every time I try to say something that just might have anything to do with all the steriotypes on black people it gets spammed with racist comments, I'm not ashamed to say myself am black and maybe some people find that no one will care but I care, and I don't know if some people think its just a joke and its not hurting anyone but it really pisses me off, I have learned to deal with it but it's just that sometimes I need to really tell people how it affects others, maybe even if they thought it was just a simple word.