That's absolutely not the whole answer and never has been.

- People who crave validation seek good looks. They want to be accepted.

- People who crave status seek good looks. They want to be awarded.

- People who crave admiration seek good looks. They want to be desired.

There are so, so many more possible reasons and motivations, and it highly depends on the individual. Someone could have all of the above or none of the above and still obsess over looks. Someone could obsess for different reasons in different contexts or with different moods.

It's not based on some infantile monkey-see-monkey-do obsession with media.

Yes, but if they only see the people of their small town, they see averages, and get a better idea of their own looks, than if they see best shots of the best actors online/in movies.