WWII and the holocaust.
Social theory shifted with artistic theory away from criticism of other cultures as the idea was seen to stir up imperialism, nationalism, and racism in varying degrees.
A sad aside is that this landfill of ideas swallowed a lot of objective criticism of other cultures and used complicated theories to mute critics and divergent ideas.
Also, if you want to get murdered, criticizing radical Islam is a decent place to start.
Not without irony, a Western society through traditional forces became benign to internal criticism, therefore you can criticize what the left sees as "its own" (The right) without much modern repercussion.
The KKK will not show up and murder you in your office, ISIS representatives might take that bet.
It is easy to be brave behind the pen until the sword of Islam shows up at your doorstep. Writers, actors, and thespians of today did not take on Fascism in Nazi Germany or Leninism in Ukraine, they took on the Young Republicans at Columbia.