The fundamental reason for having separate sporting events for young people, old people, and women (and other classifications in some sports) is that people in these classifications typically perform at an inferior level compared to adult males who are not yet seniors. If the young, the old, and females did not have their own events, these people would be unable to win much of anything in the sports world. They are in "protected" classes so they can compete with similar people.
But at the highest level in most sports, the events are, and should be, open to any human being capable of competing at that level.
In the amateur golf world, for example, the U.S. Golf Association sponsors these six events (and some others) -- one for junior females, one for juniors as a whole, one for senior women, one for seniors as a whole, one for women of any age, and one for human beings of any age or sex. This last event is the U.S. Amateur, open to anyone who qualifies. And if a senior woman was good enough, she could play in both of the senior events and both of the adult (but-not-yet-senior) events. In fact, if this same senior woman was good enough to qualify, she could also play in the U.S. Open (amateurs and pros).
In pool, we see the same sort of thing -- events for juniors, or women, or "Class B" players, or wheelchair players, etc. These groups need to be protected in this way, because most of their players would be completely uncompetitive in open events. But if people in these classes are good enough, they can also try to compete at the highest level in truly open events, which, of course, are currently dominated by adult males.
Perhaps someday women pool players won't need their own tour. But in the meantime, it's a real pleasure to see a few of them able to compete with the top men. And to argue that the top men should therefore be eligible to compete in women's events is just ludicrous.