Many of us signed contracts where 100% of the development work we do belongs to our company even in our off time. Myself included (though it's only if the work is in the same industry -- at the discretion of my employer of course). Some of the best companies hiring the best engineers do this. You are seriously limiting your pool if you favor candidates who spend their off time contributing to their GitHub. It's a bad bias to have.
Worse still, I've interviewed people who have put their employers' work on their personal GitHub, publicly and without permission, solely because of this reason. I have serious ethics/intelligence questions about those people and they become a strong no-hire every time I see it.
I guess we will just have to disagree. What works for me may not work for others. I would never sign a contract that sells all my personal work to the company I only get paid 9 to 5 for, and I don't know anyone who has. Also, it's pretty evident when someone posts their companies code to their GitHub. Simple questions and looking at the code can dispel that. If they do manage to squeak by and pass all the interviews, I don't see how a takehome would have made it any harder anyway.
Worse still, I've interviewed people who have put their employers' work on their personal GitHub, publicly and without permission, solely because of this reason. I have serious ethics/intelligence questions about those people and they become a strong no-hire every time I see it.