If you want a case of an academic being drummed out of academia for their beliefs, the best example is that of Nikole Hanna Jones, the woman behind the 1619 Project, a MacArthur Fellow, and Pulitzer Prize winner who was denied tenure primarily at the request of a wealthy conservative donor.
As for a monoculture, I don't agree, but I concede, American universities have, in modern times, leaned liberal. American universities are also the envy of the world, and objectively are the best on the planet. If it isn't broke, why fix it?
And why trust the same people who gave us Donald Trump to fix anything?