What the person is doing is very noble
But this kind of mindset is ridiculous.
They're not "hoarding it", it's their money and they have the full right to do whatever they want with it.
Your family members move out and you have a spare room, a homeless person just show up "why are you hoarding your space, give it to me!"
We have things that we like/want and not necessarily need but are you willing to give up your WiFi to save money to donate to charity? Are you willing to eat cheap, tasteless food to save and give all of they money away?
Just BC they're richer than you (even if they're filthy rich) doesn't mean they have to give away their money. It's THEIR money.