Young men, okay I'm a man in my late 30s, so throw young out as your argument. Second my wife shares the same thoughts, so, I don't want to speak to her but maybe the gender side isn't as important either.
Childless, well yes, my wife and I are both childless because of the massive problems facing the world today, mostly caused by overpopulation. I'd say being childless is more of a logical conclusion to having these thoughts rather than the other way around. It's also more likely in your assumptions that a married woman with 3 kids would be pro having kids.
I don't know what you thought you were proving, but to me it's very logical why childless people are the people who are in favor of people having less children.
Got it, sorry I didn't not pick up on the joke. I've been accused by my parents for being selfish that I don't want kids and so I take things as "only young dumb people have these opinions" a bit too personally. Appreciate the explanation