mediocre by whose standards?

I recently came across a tweet that rubbed me the wrong way.

It stated: "Mediocre people often have a clear tell: you'll often see them hanging out with other mediocre people, probably because the A+ folks avoid them."

This reeks of the kind of elitist, self-congratulatory attitude that plagues certain circles. Who determines what makes someone "mediocre" or an "A+"? By what metrics are we judging the worth and value of human beings? The premise that accomplished people inherently avoid those deemed "mediocre" is flawed and perpetuates an unhealthy way of viewing the world and those around us.

Excellence has nothing to do with shutting others out or surrounding yourself with a self-selected elite group. In fact, I would argue the most exceptional people seek out a diversity of viewpoints and backgrounds. They don't just associate with some narrowly defined cohort of "A+ folks." The insinuation that the company you keep is the mark of your mediocrity is short-sighted at best.

Perhaps this tweet was merely an attempt at provocation...
and I've all fallen for the bait.