>>520537006 (OP)
For a few reasons. TLDR: Leftists associate beautiful art with ideological enemies (reactionaries and horny men), and there was a shift in what artistic philosophy was popular in artist circles.
Notice how when you create beautiful art, the standard reaction is to make accusations of fascists, rightwing, or pornographic. "Just watch porn!" they'll scream. This is because viewing art isn't just about viewing the creation, but also imagining how other people view the art. When leftists see beautiful art and think of nazis and gooners cheering, they get a disgust response that causes them to lash out.
There was also a changing of the guard in many entertainment circles, where new artists with a new art philosophy was preferred.
This new art philosophy believed that exceptionally beautiful depictions of people (especially women) distracts the viewer from the personality and story arc of a character, causing people to never see who the character actually is, due to being mesmerized by their appearance.
The solution of new artists to address this perceived problem was to add flaws to the looks of characters: wrinkles, moles, less athletic bodies. The new view tracked with an increased focus on realism within entertainment, for increased legitimacy with the general public (ie: video games trying to be art).
The result was not just characters that looked more like people in real life, but also an emphasis on physical flaws rather than beauty.
As this view gained momentum, the social feedback of cultural development took over and exaggerated the philosophy until the flaws overwhelmed everything else.