BTB did an episode that covered competitive hotdog eating for those interested. IIRC the competitions were coed until a woman started doing well enough to get noticed. Sexism goes so deep, some folks just never want to see a woman beat a man in anything.
So this happened in Olympic skeet shooting, it used to be coed, then in the early 90s where a women won so they split the competition moving forward into men and women.
Olympic Pistol and Rifle were split in the 80s because a women tied a man (he even won the tie breaker). In pistol and rifle the women course of fire is less than the men's so you can't directly compare them either.