Perhaps thinking about this more than it warrants, but I decided the petition has two big problems, to me.
1) A call for equity, in this case, should be a call to have the women match the men. But this is a call for the men to make a concession, to reduce the distance they run, to meet in the middle, to make "equity" in some way less challenging for the women. While trying to say that women are capable and should be treated as such, by asking the men to reduce the race length as an accommodation feels like admitting that the women aren't really ready to get what they are asking for.
2) The petition invites people like me to have a voice in a matter where I should have no voice. According to previous posts (which I believe), the people who have a voice in this matter have already spoken and they don't want change.
I have asked several female runners (I'm a professor and have a lot of athletes in classes) if they want to extend their championship races to 8k or longer. Their response was an immediate and resounding "NO!" Why offer me a petition to sign when their voices are the ones that matter? If you want to collect names, they should only be from the population of coaches and female athletes, not from a population that includes unrelated fifty-year-old men.