>Most of them were were pretty unconcerned with Hitler until after the marxist-leninists were already fighting him.
Britain, France and allies were fighting Hitler in 1939. Russia was allied with Hitler until 1941, when Hitler attacked:
https://en.wikipedia.org/wiki/Molotov%E2%80%93Ribbentrop_Pac...
I love this link about a treaty, which the Soviets broke quickly, that was the direct result of a different treaty between Nazi Germany, the UK, France, and Italy that was signed a year earlier.
https://en.wikipedia.org/wiki/Munich_Agreement
It seems like the signatories to that treaty had no issue with the Nazis annexing particular bits of Europe at the time ¯\_(ツ)_/¯
And outside of Europe, a huge number of capitalist democracies didn't join in or pick a side until late 1941 (6 months after the invasion of the USSR), at the same(ish) time as the US joined.
Just i know there were preferred trading partners and aide packages from countries to one side or the other, but if Perl Harbor hadn't happened, it was by no means certain the US and many other countries would have entered the war and instead just let it settle itself.
Of course Europe was involved in the European war. Turns out Europe is only a small part of the world tho.