On a serious note, I'm surprised it took this long for the "Marines United" story to break. Nude selfies of service members spread like wildfire around the time of OEF/OIF. You can hold all the mandatory briefing sessions you want, but ultimately you're fighting against a cultural acceptance (by males and females) that it's OK to create and distribute these kinds of images, and it's not really a big deal whether you consented to their release or not. I don't really have an answer to this except to teach kids of what happens when they're indiscriminate with who they share their naughty bits with.
I don't think the reaction by leaders is about sharing nude pictures, or pictures of hot women in general - though that's not in the best taste/judgment on a site with linkages to military service.
It's about the fact current/former Marines were stalking, posting about, threatening/cajoling/cat-calling/making derogatory statements about other Marines and servicemembers. Meanwhile other Marines (and others) were either actively cheering them on, or passively consuming the content and not saying shit.
If you're the leader of any organization and find out your troops are engaged in victimizing their fellow troops - or see it being done and aren't doing anything about it - that's going to disturb you. If it's in relation to something like sexual harassment or sexual assault - where the services have invested massive resources in training and making the case those aren't endemic to service values - you've got a huge problem.
I think everyone is entitled to their personal views. In your heart you can be as racist, sexist, homophobic, transphobic, or whatever other prejudice you want to have. But, as a leader in the armed services you have the responsibility to care for, protect, and defend your fellow servicemembers period. As a leader I would question the ability of someone to serve if they engage in this type of behavior - or stand by while others do.