It’s been said the Catholicism dominates its believers’ lives and lifestyles to the extent that the yoke of communism easily slips over their heads, accustomed as they are to being told what to do. This is why, the story goes, no Protestant country has ever gone communist.
Other than East Germany ....
The Protestant Reformation began in Germany and was victorious in northern Europe. It subsequently spread via the British Empire and German/Scandinavian emigration to the U.S. No Protestant country has gone communist mainly because the Red Army never reached far enough west.
I think those Netherland countries are pretty socialist, lol. Great Britain had a socialist government for many years and they ran it right into the ground.
I don’t think anyone is immune from the lure of communism, for some reason. It’s a virus, no one knows the cure and most don’t even question why there is no cure. Sad.
Try geography. Countries like Poland, Czechoslovakia, Hungary, and Lithuania didn't "go Communist" on their own. The Russians imposed Communism on them.
You might have a good case for why France, Spain, and Italy had powerful Communist Parties while Britain, Holland, and Sweden didn't, but if those Protestant countries were further east, they might well have "gone Communist."
FWIW, the Communist Party USA was strong among Finnish-Americans, who were or had been Protestant.