Why can't people easily accept display of intelligence

Even if a woman is naturally very pretty, she still puts on make-up to look more beautiful and attractive when she goes out. If she doesn't overdo it with the make-up and her dress, no man will think she is arrogantly flaunting her beauty despite the fact that most people think to themselves that she is pretty even without the make-up. The truth is that all men will welcome and enjoy the extra beauty she has put on display. Why can't that be the case with intelligence as well? I have noticed that men become very defensive when they meet someone who's smarter than them. Why can't the reaction to something as beautiful as a smart mind be the same as the reaction to something as beautiful as a pretty face?

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