There's no doubt their behaviour was not socially acceptable. EDIT: And I'd assume their posts were not meant to be public, even if they ended up being public.

If these guys are sexual predators being suspended from clinical prevents them from being placed in a predatory position, and protects patients.

If they are not sexual predators, removing them from clinical isn't so extreme that their lives are ruined.

Dalhousie must walk a line where the male students who were not part of the group are not affected as a result. IE The Royal College of Dental Surgeons of Ontario could just say no males who graduated from Dalhousie in 2015 may practice in Ontario. Really sucks for the guys who were not in that group.

Depending on their individual involvement some of those 13 guys may only need sensitivity training, some may need to be jailed.

A rape joke is not a rape threat, or an act of rape; and any punishment and treatment must realize that. Nevertheless their classmates may reasonably feel uncomfortable around them, and I do not know what Dalhousie is required, or morally should do to address that.