[omonra]

"I think that imagining two fully equal candidates only differentiated by their volume of personal projects isn't a particularly useful exercise."

But that's precisely the point - two candidates will not be equal if one spends 20 hours a week on personal coding projects and the other does other things (however interesting or beneficial for society at large they may be).

At the end of the day the world is not fair. The question is what outcome you (as a business owner) are looking to advance. If your primary goal is to make the best product - you will have to hire the best people. If your goal is to advance women's careers - you will have to optimize for a different set of objectives.