Combination of aggression, showing off, and greater physical ability. I don't mean any of that in a denigrating way to anyone, but men and women are evolved to have different behaviours. Risk-taking is part of male behavior, and male muscle-to-total-mass ratio is higher.
Now between the womens superpipe and slopestyle events, the ladies on superpipe does more better or riskier tricks than slope. I have only seen one (kelly clark) that throws a 1080 imo. I know its a different event but i see ladies doing a double cab or chuck and not one on slopestyle
2015 Rossi One Mag 159
2015 Capita Charlie Slasher 161
It makes sense that there's a significant gap between men and women (physically, at least. I know nothing about style). Men are stronger and faster than women, even at the elite level where women have the best coaches/doctors/nutritionists and devote their whole lives to their sport. Any competitive male high school sprinter can smash the women's world record. Serena Williams dominates women's tennis but was destroyed by a man seeded outside the top 200. I can't think of any sport where the best woman in the world wouldn't lose to a promising male high school athlete.
Women's snowboarding is also drawing from a smaller pool to begin with. You'd need someone who started as a kid, and a lot of parents who would be OK with their young son getting a bit banged up in the park would be horrified if it happened to their little girl. Plus as others have mentioned, (regardless of whether it's natural or socialized) a lot of women don't feel the need to one-up their buddies or might self-select out because of the risk.
TLDR: a smaller talent pool and limited physical ability compared to the men.
Sucks for us, but whatever. I know you're super jealous of our periods.