Which would also happen to me if people of my athletic capability played that same team. What does it matter?
You're approaching it from the level of an individual rather than a population, but still, your point is flawed.
Males and females pretty much equally have the capability to develop skill at a sport. Hand eye coordination, muscle memory and sport-specific technique. Those, should you so choose, you can train. Had
you been interested and dedicated enough, at an early age, you could have done this.
Serious athletes in any sport work on their conditioning to be as close to their ceiling as possible for the traits useful to their sport. Beyond the obviously unalterable (height, for example) in most sports the differences between athletes at the higher levels are mostly skill, not physical condition.
Again, barring health issues, anyone can work to optimize their body for their sport of choice, assuming enough interest to dedicate a significant amount of their life to it. This includes you. (Again, an early starting age helps.)
The difference is that, as a population, the ceiling of the physical conditioning part of the equation is significantly higher for males. So yes, if you were to walk onto the field as you are, presumably unfit and unskilled, you would have little chance to win. But that's because you did not make the choice to develop skills and conditioning.
But the girls Stout describes
has made the decision to develop the skill and conditioning to compete at her age level. She is just as skilled as the boys, but the physical ceiling is different.
The idea of leagues and classes is to have competition where its mostly about skill, not just physical attributes. So women's sports allow a competition of skill around the female physical ceiling level.