I’m sorry for your experience. I would definitely recommend speaking to someone if it happens again. If someone makes you uncomfortable and you want to avoid a confrontation, excuse yourself and walk away.
I was in a singles group once. The group was for members over 35. It sounded like a good idea at first. But the men gawked and stared and were grinning all the time. They would hold you in a penetrating gaze. Every time you looked up someone was watching you. It was creepy and I left.
Wait a minute, these men never tried to talk to you. Do you not smile back at them or do you immediately avert your eyes? Are introductions ever made? Any mingling sessions?
Of course, all of this is non-verbal, so this being typed up on a message board can be completely left up to interpretation. So all of this is mere speculation on your part and you've built up some kind of this irrational thought process.
All they had to do was look at you a little too long and you left because of this? That's throwing the baby out with the bathwater to be honest.
I hate to say it, but that's a silly reason to be leaving. You built up something in your own mind and talked yourself out of going again. It think this was internalized.
Harmless as far as I am concerned. It's as if you are demonizing men. Heck, a guy doesn't even have to be pushy in your case, as this is what happened with the OP's encounter.
I personally think you see men as predatory, and that's not healthy way of thinking.
Also, let's get real here....I could also speculate that these men weren't attractive enough to you to not have a problem with it? Of course, as per your previous posts....."not lacking prospects". Of course, you'll be lacking plenty if you just outright leave the group altogether.
It's called life...deal with it.