I could be wrong, but I got the distinct feeling that WB was trying to appeal to little kids as well with all the toy tie-ins and everything. Also, many parents cannot afford a babysitter so even when they see an adult movie they must bring their little ones with them. I cannot believe that the perception that MOS is so dark and violent did not at all play any role in parents being apprehensive about bringing the kids. I agree with you that a lot of the other comic book movies are "dark", but Superman is always unfairly held to a higher standard and this created a lot more negative press than usual. The "perception" that MOS is more violent than the others is out there and parents are just as likely to pick up on it as anyone else.