You just agreed with your parent post. He said "A donation costs the donor much more than the tax reduction." In your example, the donation cost the donor $100

You just agreed with your parent post. He said "A donation costs the donor much more than the tax reduction." In your example, the donation cost the donor $100, which is much more than the tax reduction of $39 + $20. But on another point, didn't you just double count the tax? You donated $100 of bitcoin, and you write it off your taxes (so not having to pay that $39), but you just counted another $20 somewhere.