It's free labor, and companies love free labor. They claim to value candidates that produce open source, but somehow those who toil night after night on their passion projects never seem to see any job offers materializing as a result. At best they get recruiter spam (for which many here argue they should be grateful) inviting them to submit themselves to a whiteboarding carried out by an arrogant 20-something often fresh out of college and eager to assert their dominance.