The quintessential(sp) question is : Why is the Vatican silent?
The Vatican doesn't run Notre Dame; it's mostly run by a lay board of trustees which is heavily populated by Chicago fat cats. "Chicago fat cats" are pals with the Daley machine; the Daley machine produced Obama ... you get the picture.
The only thing the Vatican could really do -- aside from a verbal rebuke, which would be ignored -- is act together with the local bishop to take away Notre Dame's right to call itself a Catholic university.
They have chosen not to do that.
So far.