I think it helps to bring it back to the real world, and not simply rhetorical hypotheticals. A lot of the otherwise well meaning people fall for the false premise that there is somehow vast amounts of trans women in women's sports, but there just isn't. They accept the idea that it's a popular occurrence for a male athlete to transition solely to dominate the women's sports field, but that just doesn't happen in real life.
In 2021, just nine of the 174,000 students participating in high school sports were transgender.
It's really just a plain lie, and not at all worthy of serious consideration. If people who are presented with these facts still choose to be transphobic, then they're simply showing their true colors and using this as an excuse.
Honestly, it's really sad there are so few. I find it horrifyingly depressing to imagine being the single transfem high school athlete in an entire state, and being aware that her state politicians are spending their time debating and passing a law in which the only material outcome is preventing her, personally, from competing in sports.