You could try complaining Jamie, explain to them that banning this website is an infringement on free speech. This site isn't a hate site, it is a refuge for those who wish to discard their religion freely and face abuse due to these actions. The uni is only encouraging this attitude of penalising apostates for making a choice they should be entitled to, not only that but they are participating in removing the few outlets they have to discuss such issues. Hopefully they will listen, if you can find other atheists to join you in complaining then do so. The more the merrier.
Good suggestion.
Jamie, is there a secular students alliance or some such group on your campus? You may want to get a few students, perhaps a faculty member who is sympathetic to atheism/secularism, to write to the Uni's administration as a group.
By speaking up, you could be helping others who are questioning their religious traditions too.