These were places where men should be able to expose themselves and fully jack off. The fact it's illegal is ridiculous. As a horny man who is aware I have to keep it in my pants, I appreciated having a place to stand up from my seat, pull my pants down, and let everyone see it standing up along with my pubic hair.
I was very horny exhibitionist then (just as much now) and also liked exposing my erection getting my pants down and openly masturbating, cumming. That was my thing, and once I got my pants down getting more and more worked up, the other men did too, getting theirs down, and we'd watch each other panting exaggerated facial/body movements as we were about to cum. Doing it in front of the computer now isn't the same, but we have access to these old films.