It undermines the art if the lead characters are written from a disingenuous and/or ignorant place. That's kind of it.
Advantaged people in Hollywood win but also feel bad about winning: La La Land, written by a man who won young.
The above is reductive, but not wrong. The writing (sans the very end) is the weakest part of the movie. I really enjoyed it, but it's kind of tone-deaf and the only reason it got as far as it did in the Oscars is because Hollywood loves movies about Hollywood. Come the fuck on.