The thing with human nature is that you automatically label somebody on the first thing you notice.
"Hello. I bought this t-shirt the other day and I'd like to return it. The person who served me said I could return it if I didn't like it when I got home."
"Oh, ok, sir, do you know who served you?"
"I think it was your manager, the tall, blad bloke.""
Oh yes, I know who you mean, that's my manager. Let me call him."
*assistant wonders off to make a phone call.*
"Hello Dave, I've got a customer here who said you said he could return an item."
"Yeah? Who's that?"
"Dunno. Some poofy black guy."
"Oh yeah, I remember serving him and I didn't say he could return it."
"Ok, I'll tell him."
*assistant returns*
"Sorry, sir, my manager says you can't have a refund."
"WHAT! He said I could."
"Sorry, sir, that's company policy."
"Listen you fat bitch, lightbulb head said I could."
"I'm sorry, Sir, if you continue to talk to me like that, I will have to call security."
"Call security then, see if I care!"
*assistant calls security, security mans arrives*
"What's going on here then, young man?"
"That fat bitch won't give me a refund."
"Sorry, sir, I'm going to have to escort you off the premises or call the police."
"Don't worry about it, old man, I wouldn't want to give you a heart attack. I'm leaving anyway!"
*minces off*
As utopic it would be if people didn't categorise people, life would be boring and impossible if we didn't label people or take the piss out of their most instantly notable feature. People choose to be offended rather than actually feel offended I think.