"Ah", I hear you say, "but philosophy does not fit this pattern, because the people who do it aren't smart. They're all at best of mediocre intelligence." (is there another explanation of the poor understanding you refer to?)

There's no fool like an intelligent fool. You have to be really smart to be as stupid as a philosopher.

Even in antiquity it was remarked that "no statement is too absurd for some philosophers to make" (Cicero).

If ever one needed a demonstration that intelligence is not usefully thought of as a one-dimensional attribute, this is it.

Philosophical progress may tend to take the form just of increasingly nuanced understandings of its problems' parameters

When I hear the word "nuanced", I reach for my sledgehammer.