The biggest threat to academic freedom comes from students and faculty who believe psychological safety from hearing viewpoints that they disagree with is more important than the ability to articulate arguments or listen to the opposing side in a sober, thoughtful manner.
Early on, the great threat to academic freedom perceived by the movers and shakers of higher education was meddlesome trustees, big business and state legislatures who were willing to invade campus with narrow and parochial views and shut down the free speech of academics. Most of us think that is no longer the great danger. The great danger is not coming from outside of the university, but from within it.