Stupidity is one thing, ignorance is another matter altogether, and rudeness, arrogance and or other thoughtless behavior is ugly no matter how it's built. No lens, no matter how clouded by lust, can take the deep crease of failure out of a face behaving like an ass.
On the other hand, some of the most tender, earnest and gentle 'gentlemen' I've ever known were not particularly scholarly or bright, but they have a wisdom and kindness some of the better educated have failed to claim, so IQ matters little when kindness amplifies beauty.
And the occasional just plain dumb remark or action...comes with testicles, and can be over-looked if it's not happening with alarming regularity. (See requisite kindness noted above to offset those 'doh' moments.)