Starwolf, there are many wonderful things involved in shaking a lulav and esrog- many esoteric kabbalistic concepts. Yet, lulav hagazul is passul. There are lines that aren’t crossed no matter how great the reward. No matter what the hidden manuscripts are in the Cairo genizah, if getting them involves violating issurim then we do without. I’m not saying one has to violate issurim to get them, but the ends don’t justify the means in yiddishkeit.
There is promiscuity everywhere if you know where to look for it. Yet, some environments are more conducive to it than others. If you think the typical office is as promiscuous as a college campus, then you are lacking knowledge about one of them.
I’m not saying attending a mixed college is assur. But the sakanos are there.
The Lubavitcher Rebbe audited classes. He was not an active student at the university. The Rav ZT”L did attend a mixed university, but universities were much different back then. The pritzus and “anything goes” mentality in today’s colleges didn’t exist.