You're absolutely right. I notice this on facebook especially.
I'm a writer, and even though I may not sound all that articulate or classy on this site, I'm actually really one of the best in the world at what I do.
And what I can tell you is that I can tell RIGHT AWAY when people are trying to use big words, fancy syntax, or different phrasing in order to try to keep up with me. Normally they'll give it away because they're using a word that is clearly a synonym of the simpler word they wanted to use, but it doesn't quite fit into the sentence because the meaning is just slightly different.
I've seen guys that are actually "well spoken," although I don't use that phrase because, like you said, people tend to call blacks well spoken as if few of them are.
The word I use is "eloquent," and honestly, eloquence doesn't come from using big words- it comes from being clear, concise, and having a certain flow (like a rapper) in your sentence that you simply can't teach.
There's a reason the word is not often used, and that's because most people communicate like cavemen, and most are not born with that flow. But when you hear it, you know it.