We probably should just avoid saying "average" and use "mean", "mode", "median", or whatever we actually mean instead.
It’s only when someone says something like the average family rather than saying the average income when things get ambiguous. Typical on the other hand is closer to mean because it’s tossing out outliers.
It is also pretty absurd to assume without explanation that a minority who are especially bad at management have even their minority presence in management given that if sucking matters it should correlate with some type of failure that eventually correlates to drop out.
In fact, it's the other way around - a proof that the person suggesting this doesn't know math.
If 80% are skilled at 1 and 20% are skilled at -100, then most are better than average.
Or: Imagine a room of people. Bill Gates walks into that room. Most people are now below-average wealthy.