Why don’t they leave?
Do you remember when Charles Curran was at Catholic University?
He was always the first person the press ran to for an opinion (always heretical) about sexual issues.
Finally, in 1986, Cardinal Ratzinger ordered him out. Curran went to Auburn University, a Protestant institution.
He hasn’t been heard of since.
“Since he continues to dissent from orthodox Catholic Church teaching, Curran has been deemed, by the Vatican, unfit to teach Catholic theology”.
http://en.wikipedia.org/wiki/Charles_Curran_%28theologian%29