Edit, I just had the thought that maybe this is too broad to get much traction, and would like to add that responses focusing on just one nation would also definitely be answers. I don't know exactly what the response rules are regarding answering just a part of a question, but it might be hard to do justice to NATO overall, and I'm more interested in how individual countries reacted anyway.
(So originally I asked this as a follow-up to the response about Labour's dramatic victory in 1945 UK, and in the brief-ish reply it was suggested that I post it as it's own topic. I also just saw this poster on /r/propagandaposters that made me want to expand it to the rest of NATO generally, in addition to the UK. )
It doesn't seem to have been as drastically demonized within the rest of NATO as it was in US, which still suffers wicked strong, irrational, anti-socialist sentiment (I say irrational to contrast what's common rhetoric/opinion to actual criticism of socialism and its implementation). For instance, much of Europe proudly declares it's socialism, to much success in a lot of cases, something that before recently would summarily tank any US politicians career before it began.
However, the UK was the third nuclear power, iirc, followed soon after by France, so it must have been affected somehow just because of the nuclear spectre. On top of that--as was pointed out in the reply that prompted me to post this--was that the UK (and other NATO countries) were totally dependent on the US after the war, and needed to acquiesce, at least in part, to it's foreign policy.
Still, it seems to me based on my (outside) perspective of the general European sentiment on socialism and social programs that there just isn't such a taboo around the whole thing there. Was there just less conflating (stalin's) communism with more general socialism, or was it something deeper? Or am I misguided in my assessment of the feelings in europe about european socialism?
Edit 2, Also, I know NATO isn't only European countries, those were just the socialist examples that seem to run counter to US sentiments.
Just a sidenote on the Norwegian story. Firstly. That propaganda poster was made before the war or maybe early war. It was made by the norwegian "fascist" party Nasjonal Samling (short: NS). It was probably made by the artist Harald Damslet. It portrays soscialism as the same as death. It was however not uncommon in the 20s or 30s for right side parties in Norway to portray socialism or parties considered socialist, as such. Second. During the war when the allied joined forces with Stalins Soviet, things changed dramatically. Uncle Joe as Stalin was called, had huge kudos from 1943 and onwards with the Soviet Red Army pulling the hardest punches to nazi-Germany. In Norway the red army actually helped free northern Norway. Norway also had a former revolutionary party in power in 1945 (actually from 1935). They were by 1945 however socialist or radical social democrats. Therefor in 1945 the norwegian society as a whole and the goverment as such, was not entierly sceptical towards the soviet union or socialism as a concept. Main tenants inside the norwegian workers party, whos was in power, was leaning towards that direction in the early phases of the cold war. By 1948 things had again changed however. The soviet promises for free elections in Poland and Czechoslovakia had not been fullfilled and in late 1947 the communists, with help from moscow, seized power in Czechoslovakia. That made the leaders in norway, in specific Einar Gerhardsen, to go on the offensive towards communists and the Soviet Union. During the famous Kråkerøy-speech he not only attack the czech communist power seizure, but also attacked domestic communists and communism as a whole. This is a turningpoint in norwegian policy towards socialism, communism and the soviet union. We of course also have to look into the american pressure on western european countries to take a stand. Countries accepting american help through the Marshall plan, had to guarantee to uphold free market trade.
