They didn't. All the badges were either offered on Adafruit, a few non-BSA sites, or designed by Hacker Scouts. Hacker Scouts has permission to use all the badges for the skills it teaches. For reference, here are the BSA badges: http://www.boyscouttrail.com/boy-scouts/bsa-merit-badges.asp

Actually, each location was just started by a few parents getting together and deciding to start a group. The primary role of the Hacker Scout national organization is to help local groups get started, and provide curriculum. (so don't worry if you suck at teaching) If you want Hacker Scouts in your area, you can make it happen!

I would suggest becoming a mentor. Hacker scouts has mentor training sessions where you learn all the skills so you can help teach them. I've been mentoring Hacker Scouts for a while now, and I've been taught how to weld, cnc mill circuit boards, and a lot of sewing techniques.