You want to compare the Ukrainian conflict to WWII. This is ABSURD. Firstly, there is a major difference. In WWII, the US was allied with the Russians to fight against the Nazis. In Ukraine, the US is allied with Nazis to fight against the Russians.
It is not disloyal to criticise your country when it is doing something wrong. THAT is one of the greatest tenets of what you call "the system we worked so hard to build".
This war was 100% avoidable, but it was something the US deep state was 100% dedicated to having - ever since Zbigniew Brzezinski wrote The Grand Chessboard in 1997. And the deep state finally got its wish starting with the CIA-backed Maidan Coup in 2014.
I believe that even Victoria Nuland knew on some level that Russia would always prevail on the battlefield. But the purpose of the whole exercise in Ukraine was not to defeat the Russian Army on the battlefield, but to "bleed" and "weaken" Russia so that Putin could be overthrown.
Whatever happened to the Ukrainians was, for the US, just an afterthought.
Remember that famous Kissinger line: "To be an enemy of America is dangerous, but to be a friend of America is fatal".