help me understand why rascism occurs

as i've grown older i've tended to avoid asking many why questions cos the answers are too complex. but i'm interested in this one too much.

i think the reasons are probably different in different historical contexts. in the UK i can see (thought not totally agree with), why people are anti-Islam, with the attacks n media hype n so forth.

and i can see why older people looked down on blacks, cos when they entered the UK they came into the working class, and so the tendency for crime n so forth would have been greater, hence a bad reputation.

but now with loads of respected blacks in prominent positions, people are still rascist. is it just because they look different, and people dont generally lyk things that are different? is it as simple as that?
__________________

racism exists because we still havent weeded out the "moronic dipshit" gene.

also has to do with human desire to control, belittle and otherwise feel superior over fellow man.

protip: having control over another hauman doesnt prove you're better. it just proves you're an insane megalomaniac. the other problem stems from ppl unable to face their own failings so they make themselves feel better by belittling others.

hence 4chan.