all i really see is women having a place where they can run, raise money for charity, have what some of them feel is a safe space to do so, many who haven't raced before, and some men objecting to that and in essence wanting to take it away.
there are plenty of men only races and events.
if you go to any mainstream event, the vast majority are male orientated as it is.
due to bio differences, pretty much a high school boy runner will be better than female Olympians. it's just fact. maybe women enjoy being able to run and compete and be near the front of the field.
just like if there was a gay race (as far as i know there is a gay sports competition/worldwide event), or races for people with disabiities, or a race for deaf people, or a race for Asian people. as a white woman i wouldn't try to take that away from them and argue there shouldn't be a race for Asian people. if you look at athletics (track and field) each event is separated by gender. is that sexist? there are women's football matches - men can't take part. i was banned from my primary school football team because i'm female. even though i had been selected, and was in the newspaper in the team photo. there are many many instances of gender being segregated.
what would be nice would be if people could celebrate this amazing event and the amount of money it raises. i wouldn't petition to join a men's event if there were similar women's events, ie i'm not excluded. just like the prostate cancer events and man on the run events. i would respect their space instead of intruding on it. really nice to read the explanation above.