To them, all in the world is the individual perception. And because all in the world results in differential outcomes to individuals (oppression), it is incumbent on people to destroy it (the world of man) in a very practical sense, and build utopian perfect democracy in its place. And to guarantee equal outcome.
They started to introduce this crap when I was an undergraduate. It's intellectual carbon monoxide. Thank God I recognized it for what it was when I got a whiff of it and got out of my then-course of study.
It's a whole 'nuther level of stupid.
It's a fundamental rejection of God, His authority, and His objective reality as expressed in creation.
“objective reality”
They vehemently insist no such thing exists. And that it is incumbent upon every individual to not only perceive their own reality, but to express it in real terms.
Making human society and civilization impossible.