The survey didn't measure accepted contributions vs. rejected ones. It just asked whether people contributed at all, and then sized up the demographics. Simply put, 75% of contributors are men and 25% are women.
I don't follow you.
"[I]t's time to get involved in the online space and help build the future of knowledge and technology."
...is not constructive?
Your first reason for not contributing is actually one of the most common reasons. Your second reason sounds similar to reasons offered for why women aren't as well-represented in the political blogosphere.
Wikipedia initially grew out of hacker culture and the free software movement in particular, with a big early boost from Slashdot -- all of which are historically male-dominated.
I suspect that whatever keeps women from joining those communities in large numbers must also be in play at Wikipedia.
But I don't know what those reasons are.