From the perspective of the layman, I get the concern with "non-consensual" pelvic exams. It's invasive, seems unnecessary, and "immodest" (though, as calvn points out, I think being concerned about these issues in the context of having your vaginal cavity shown on 46" LCDs x 4 in the OR is pretty silly). Hell, I remember reading these stories as a pre-med and being mortified and squarely on the side of the patients.
That said, these opportunities may very well be the only time students get to see this pathology. The only opportunities I really had to do a quality pelvic exam where I felt I had the time necessary to think about what I was doing were during gyn cases after the patient was anesthetized. Given that the resident will definitely be doing the pelvic exam (to tell the attending the findings) and that the attending will also be doing the pelvic exams (can't trust those residents), it seems somewhat silly to now all of a sudden have an issue with medical students doing a third exam. The problem with the OB/GYN stuff specifically is that it can be difficult to get any sort of meaningful exposure to it exactly because it's "sensitive." As a man, I was probably refused to be allowed in the room ~50% of the time on the out-patient portion of my OB/GYN rotation. In the other 50%, I was so worried about not being a goofball on an awake patient that my exams were brisk and superficial at best. Sure, I knew I wasn't going to be an OB/GYN while doing the rotation, but I still want to learn this stuff and at least have some kind of exposure to it.
The fact that patients are at a teaching institution is also worth emphasizing. If you don't want this kind of "attention," then avoid going to a teaching institution. Plain and simple. I try to avoid being completely insensitive to the issue, but in the context of everything else that goes on in the OR and in the context of being at an institution that has a major goal of education clinicians, I think the argument is pretty weak.
I think it goes without saying that doing pelvic exams when otherwise not indicated is definitely crossing a line.