When you segment based on age and sex you are dividing up people based on their starting conditions - people who were born in the same year, and with the same s

When you segment based on age and sex you are dividing up people based on their starting conditions - people who were born in the same year, and with the same sex, compete to see who is the best. When you divide based on the attributes that matter for the sport, you are basically just pre-ranking everyone and bucketing them so you only compete against those who we predict will do as well as you. Which is fine for more casual levels of sport, but isn't particularly interesting to watch. No one wants to watch a competition to see who is the "best of people we think are ranked 100-200" since it is an arbitrary grouping. They want to see people compete to be the best woman or man in the world. Dividing based on weight makes sense for some sports since it is an added constraint that people compete to optimize their strength against. But dividing based on strength just moves the competition from the actual competition, into the ranking process.