I think making it an assignment to photograph each other's penises and vaginas is a bit too far. You shouldn't put students in the position. If you want them to photograph nude people, then they should hire willing models, and not be asked to volunteer themselves into these uncomfortable situations. If they volunteer to model, then that's okay. Also, making the class look at photos of your own penis, if you're the professor, is clearly wrong. They may be artistic in nature, and I have no problem showing them pictures of the penises and vaginas of professional models. But having the class examine the pictures of the professor's penis clearly seems out of bounds. I also think he crossed a line when he propositioned a student for sex (asked her if she's like an "old friend with benefits") and described in detail an erotic dream he had about another student. There were dozens of other complaints about his as well. It wasn't a one time incident that got him in trouble.
I have a fine arts degree and agree that Americans can be pretty prudish in general. But in art school we were never asked to do anything anywhere near that questionable. There were a few awkward moments, as is always the case when new to nude bodies, but it was always handled in a professional manner. This clearly was not.