I don't understand this. Why should my utility function value me having a large income or having a large amount of money?

With that being said, I certainly don't give anywhere near half of my income to charity and it's possible the values I actually live may be closer to what you describe than the situation I outline. I'm not sure, and not sure how it changes my argument.

Sounds like you answered your own question!

(It's one thing to have some simplistic far-mode argument about how this or that doesn't matter, or how we should sacrifice ourselves for others, but the near-mode nitty-gritty of the real-world is another thing).