Minorities and Slang?

I'm Hispanic first off. I get a lot of flack for speaking properly and "talking white". I'm sorry, but when did good diction become something that only caucasian people can do? Also, when someone uses slang I've heard it considered "talking black". To me, if we are going to define someone based on the way they speak then you should break it down by educated/uneducated (sorry if I offend anyone) or proper/lazy (I think this is really what sums it up as words and phrases being shortened). I just thought of this when someone got offended from a commercial where a character was dressed in baggy clothes and wearing chains and said they were making fun of blacks. I've seen white people dress that way so I didn't see anything wrong with the commercial. Your thoughts please.