“Only the West has bought in to this nonsense...” Only the liberals in the West, you mean.
Digressing a little... Liberals depend on their ability to manipulate groups rather than individuals, so populations have to be broken down. And “culture” is one way. Other ways are skin color, “sexual preference”, age, wealth, age, etc...
In other words, the liberals would love nothing more than to have groups (in this case, cultures) of people migrate to America rather than “individuals.”
To me this is what it’s about.
Unfortunately, our government and educational system has bought into multiculturalism almost completely. It's not just liberals because few in government or education speak out against it. Silence is agreement in politics and the education.