"said that it was impossible to tell whether a pull request was ignored out of bias, or just because a project owner was busy or knew another developer personally."

This is exactly what I've been saying. Open source projects are very political and studies like this don't really show sexism, it shows favoritism.

This is what happens when each project is essentially a dictatorship with a small group of leaders that can pick and choose commits.

We should be striving for more of a meritocracy, rather than favoring someone because we like them.

The same thing happens with political beliefs as well.