Note the way he picks on a woman in the audience for no reason to her surprise and bemusement. If you've read "Surely You're Joking..." you'll recognise it as one of his pick-up techniques. I'm a massive Feynmann fan, he has such insight, wisdom and humour. All of us have foibles and we see (IMHO) one of his in this one. They're all adults and I can completely forgive him for it just as I could if it was him putting his index finger up his left nostril and having a good dig while on camera. Not super pleasant to watch though. Adults deciding or not to have sex is fine. Being jerks to try and do it, eh, no more than yuk but, yeah, yuk.