A woman I knew (environmentalist) always only used this term when she was driving home a point to someone else who she thought was dumber than her.

"I'm going to talk in a way that you stupid people can understand."

That's all it is to them; with an air of royalty, they reluctantly wade out into the "common-folk's" language to show their benevolence, while retaining their sense of linguistic superiority by using the term as a covert intellectual slur.