The Establishment has already been proven wrong.
United we stand, divided we fall. The left understands this.
Unfortunately, very few public figures are allowed to question the "Diversity is Strength" mantra by asking obvious questions, such as asking those making this claim to provide historical evidence in its favor, or to give a single example in society where cultural and social differences facilitate rather than impede things going forward. Because political correctness is a religion, all the facts in the world and standard for proof don't matter.