Ok, let's examine principle. There are many food charities for starving people in foreign countries. If Bob does not donate to those charities, does that make Bob a murderer?
Donating other peoples' money is not virtuous. Donating your own is.
Stick to working on programming languages that nobody uses, Walter. The pseudo-intellectualism on display here is embarrassing.
1) What he did was illegal. Those aid programs and the funding they were to receive was written into law by congress - elected by the people - with overwhelming bipartisan support
2) No of course we are not necessarily morally obligated to donate aid in perpetuity. We can decide to stop if we want to. But it was not Musk's or even Trump's decision to make. But since they assumed that mantle of illegitimate authority, they assumed the moral blame that comes with it.
(And yes, every Trump voter also shares significant moral blame for the deaths of all those people. Atrocity was a predictable and likely consequence of a Trump vote in 2024)
its not about virtue and its not even about starving. Its about making a global economy more stable so the world is richer and the US almost always profits from that.
I am donating my own. But that's besides the point: shutting down an existing aid program, especially in the way it was done directly kills people. You can't just handwave that away as 'we are not donating'. You were donating. The donations were done to such a degree that lives depended on them. If you then shut it down without so much as a slow withdrawal to avoid systemic shocks then you are doing this out of cruelty, not because you want to save some money.