> So he’s going to selflessly donate it to himself to save himself from taxes? What a hero.

You don't really "save yourself from taxes" by donating money to charity.

Option A: sell stock for $100, pay taxes of $20, spend $80 on yourself Option B: donate stock of $100 to charity, and spend $0 on yourself

Which of these options leaves Gates with more money in his pocket to spend on himself?

Giving money away doesn't save you from taxes on your income; you just forego the income entirely. The money is gone. It's no longer yours. Why would you be paying taxes on it?