It's not that they are better educated per se, it's that they study the English language and it's mechanics (grammar) and so speak better because they have studied it. Most native speakers don't study the mechanics of their language, this is why you get descriptive grammar not correct grammar. They don't know any better.

I think saying they are less educated is a bit harsh though, perhaps it's true of English grammar, but to give a blanket opinion to the rest of their education level is unfair.