The reason?:

The official reason given by university administrators to supporters of the club -– which included 20 of the 23 members of the school’s Student Association and representatives from multiple other campus student groups –- for the rejection was that administrators fear such a group would become an advocacy organization.

Ryan Fecteau, speaker of the Student Association and a former director of the yet-unrecognized CUAllies group for LGBT and allied students, says the group had been trying to convince administrators for nine months that “the organization would not actively promote causes that might be in conflict with Catholic Church with regard to homosexuality.”