Why wouldn't I want to take every possible factor into consideration? If I have two people, one of whom has a github with lots of personal projects and the other one does not, I'm naturally going to get a better sense of the github developer in terms of their overall capabilities.

That doesn't automatically make him the better candidate but it definitely gives me more information to act on.

If people don't want to or can't work on personal projects then that's fine, but I'm not going to ignore the people who are passionate about building their own stuff.

Not unreasonably. Like it or not, at else being equal someone with more current experience is probably the better employee.

There's this feeling that employers should just take the next person who fits some quota because to pick and choose is to be biased which has somehow become a bad phrase. My employer literally pays me to be biased. My job skills include having appropriate and helpful biases.