> Also I'm not sure I'd call it a sanction since it's coming from a private company, not a government.
It's following sanctions, which blacklist all big Russian banks and remove them from international banking and financing arrangements. Even if Visa/MasterCard aren't explicitly prohibited from dealing in Russia, how are they supposed to move money around with the sanctions in place? It's because of the sanctions.
> If I were any country right now I'd also take it as a warning to not depend on Mastercard or Visa given the immense power they hold
They can try not invading other countries, that seems to do the trick. Joking aside, countries like France have their own independent networks ( Carte Bleue in France) over which payments pass in some scenarios ( honestly couldn't tell, but for instance there are weird cards from some banks that only work on the CB network and don't outside of France, even if they're supposedly Visa/MC).
