This is largely a story about excessive copyright duration. The casting requirement for this 70 year old play is based on legal threats by the estate of the author who died over 30 years ago.
Please read the article first, not only the title. The above comment is completely correct. Whether their approach is acceptable though, that's another story of course.
Or if they read the policies of the venue and adhered to them, the play could go on. Saying "you can't do X at this venue" is not the same as saying "you must do X".
...but the university is doing exactly that - forcing diversity for diversity sake. The play was written to be all male and they refused them the venue as a result of no women being called to audition for a role that isn't for women.
Hold an audition allowing all people to try out, and if a woman does get cast because she is best for the role, read the prepared statement before the play indicating the rights holders don't like it.