This is more generally phrased than the very lawyer-written EULAs you generally find, but it's not unreasonable or unprecedented.
Embargoes and sanctions have no ethical force behind them anyway. They are merely a way to harm poor people while ginning up more pretexts for more wars. Anyone who can oppose such monstrosities using git should do so.
It's fair for a software author to not want their software used to make the world worse. I think you have a very different interpretation of "charitable interpretation" than I do.
As for embargoes - sure. It's just an example. There are plenty of other less morally ambiguous things too.
Whether it's enforceable, sure, that might be questionable.
If I cared about a git client for these platforms, I would file a bug about the license. Fortunately that is not the case.
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