First they Came For The Racists

[Papewaio]

Recently a group of young men affiliated with the Sigma Alpha Epsilon fraternity drunkenly chanted nigger on a bus.
Will someone explain to me how a public university can expel these students?

First the racists came for the people of colour, then they came for the ones who stood up for them and then the rest were herded up.

I think you are quoting the wrong side of the issue here. The racists foster an environment of hate that allows the like of KKK/neo-Nazi's and other hate groups to operate. The university is going head on against that, so they are in fact stopping the 'First they came for xyz'.

The university has a duty of care to its students and staff. I'm sure that someone stating they will lynch someone using a racist slur falls into one of if not many categories that would be written up as conduct that can get you expelled.

On top of that any endowments be they federal, state or private may be lost if they let the behaviour continue as it would be seen as providing a haven for racism.

tl;dr

Its the 2010's man, no longer do you get told by a racist where to sit on a bus, instead the racist on the bus now gets kicked off. Same applies to university.