You haven't been able to give them nothing for over 2 years now. For this particular bundle, the minimum split for Humble is 30% and the default split is an insane 45% to Humble, 50% to the company and 5% to charity.

Humble is unfortunately still coursing by on their old reputation of being charity-friendly, but they changed to be one of the worst players around years ago. That goodwill from back then has really been depleted.