In the first place, so much of the aesthetic is based on gangster culture. Black gangster culture specifically. Based off of the actual real problem of black violent gang culture . How can that be considered good in any way?. And the music itself is low class, simplistic and has no real melody. i don't know why anyone likes it to be honest.
And White or Asian people copying it are worshipping black gangster culture because so much of hiphop and rap is based around that. Just look at the lyrics and music videos and what the "singers" wear and how they conduct themselves. All the tattoos , too many metal piercings, stupid amounts of jewelry (again , its based off of materialistic gang culture) just all around uglyness , rude gestures and behaviors, trashy . In general its all just vulgar.
And why is something that was invented decades ago always promoted like its "cool and modern"?
Low barrier of entry and the fact that we are probably in the middle of its popularity peak makes it so we see all the trash. Nobody remembers the trash from the 70s and 80s because nobody re-releases the crap on best of albums.