Hey Greeney, which locker room? Which swim team?
What's the point in asking. For some people, the simple answer that fits into their notion of the way things always have been will always be the correct answer, ignoring any evidence to the contrary.
Whether they believe that the Earth is 6000 years old or transgender people have only been around since the '70s, it's just as intellectually bankrupt. The icing on the cake is when they accuse other people of having trouble with viewpoints that don't agree with their own.
Such people remind me of my dad (pre dementia); I used to visit my parents on approximately a weekly basis (they lived nearby), we'd talk about stuff, naturally politics would be a topic at some point during the evening. I'd mention something about American current events, to which my dad would respond along the lines of I'm always ragging on about America, I'd explain my point, to which he'd grudgingly agree, then the next time I visited the process would be repeated. No doubt he forgot entirely about information that didn't agree with his world view.
Greenman apparently honestly believed that despite hundreds of thousands of years of human evolution, gender expression only suddenly "got complicated" in the last fifty. Any honestly interested person would eat crow and review their related beliefs on the topic, but he just carried on repeating his usual anti-trans schtick: Transpeople make sports complicated so just shut them out completely. The nugget of information which states that transgenderism existed earlier in time than the seventies will be ignored like a puzzle piece that doesn't seem to fit anywhere, if it hasn't already.
Of course, he doesn't really care what someone identifies as, nor does he care about sports, yet every time that transgenderism is mentioned, he reaches for the (likely 100% bullshit) story about people pretending to be trans to get a leg up in sports. He doesn't agree that transgenderism should be a thing, so he reaches for what he perceives to be the easiest argument: Sports isn't meant to be fair, except when it is, just as long as it doesn't include transgender people then it's fair. That makes sense, right?
IMO from his comments in his thread, half this bullshit is based on a founding principle that men are superior to women. It's downright offensive to him that a man should compete with those less than themselves. IMO it's absolute lunacy to believe that gender brings some kind of universal unbeatable advantage to warrant such a notion; even if I considered myself to be good at a particular sport, I'd be completely willing to accept the possibility that a woman could absolutely trounce me at that sport. After all, many sports illustrate the point perfectly that "it's not what you've got but what you can do with it", that even the most experienced pros get caught off-guard by an unexpected tactic. Strength and speed do not always win the day.