this is a very diplomatic summary:
my recollection is that Musk talked smack on the UN and other orgs and bragged that he could solve world hunger with just a fraction of his cash
so they called his bluff and he refused
On the day before Elon Musk becomes the world's first trillionaire, all I can think about is that time in 2021 when the head of the UN World Food Program asked Musk to donate $6 billion to save 42 million people from starvation and he refused.