Why are some people so pretentious about music?

I had this kid in my auto tech cl ask me why I was trying to be black after I told him I make rap beats for fun. I told him making beats doesn't make me black. He then tells me that it doesn't take any skill to make beats and that I should listen to bands like system of a down. I told him it does take skill. He told me it doesn't you don't even play instrument you just sample stuff. Which I couldn't argue I do sample but mainly as the chorus and give the verse parts a little more substance. But it's more than that I have to add drums to it sometimes using an mpc other times I'll play it out on real drums using a mic hooked up to a computer. I use a lot of synthesizer and piano so I play that out on my midi. But He just kept telling that I need listen to the bands he liked and played me one. I bared through it wasn't something that I like but it wasn't mortifying. So I try and play him too much soul by chiddy bang and he flipped out on me yelling "turn off that hippy music!" which is weird cuz chiddy bang is rap. But why are people so stuck up about their own music and mainly the metalheads at my school that do it.