Why can't people these days meet someone without putting a lable on them?

Okay well EVERYONE when they first see me thinks that I'm some dumb lil wigger, wanna-be, ect. they all UME i talk like im a thug, only listen to rap, ETC, BUT all my close friends know its not even close. in face not much rap do i even like anymore. i like some, but the majority of it blows, especially Soulja Boy(sorry but its my opinion XD). i listen to rock and metal mostly like Killswitch and Slipknot, but i wear baggy jeans, south pole, throwback jerseys, timberlands, forces, and the rest of the "gangsta" like cloths. See I don't get why I cant dress how I want, and still be allowed to listen to what I want. Im actually a drummer, and a vocalist, but when I tell ppl they laugh like im joking. basically im just asking, why do people have to be like that?