The comment below me won.
The only argument i could see for pg-13 is I don't think teachers would have to have waivers from the parents in order to show it to their kids in class. Could be wrong depending on the school system though.
I wish it was something I could do for those poor bullied young men....I wish I could hold each and everyone of them in my strong arms. As I stoke their hair and wipe their tears and show them how a real man can care for them. Their young tender(so tender) emotions need some love and attenion.
I think they should have left the rating as R instead of going with the it being unrated because it will limit the amount of screens where the movie can be played. I remember going to see Schindler's List in Jr. High even though it was rated R. The same thing could have been done in this case.