Yeah, it's been fascinating. I've seen numerous articles by trans men complaining that they're excluded from conversations like this. But they're not being excluded, it's just not controversial for a biological female to compete against males.
The fact that nobody is talking about trans men is the clearest evidence that this argument isn't about transphobia but about fairness. But I firmly believe that trans men have just as much right to opportunities in sport, and they won't get them while they're competing against biological males.
Creating a separate league brings its own problems, but it's hard to see a better solution.