I'm a white male, very active on Stack Overflow, and working to become more active on Github. Still, I find acadien's observation very interesting. We should aim at trying to find the real causes of the situation, instead of being offended, just because someone pointed out something that clearly is a fact.

Suggesting that white males are more selfless is a bullshit answer. Maybe they (we) are the only ones who have the right combination of being educated and having enough free time? Maybe this has something to do with gender stereotypes? Or gender roles and woman usually having much more additional non work related responsibilities? I don't know. But it's worth asking.