In very many ways, it wasn't propaganda. I'll cite my sources first...NSC 68, Kennan's Long Telegram, Mr. X Article, Odd Arne Westad's 2000 Bernath Lecture (Diplomatic History), Rosenberg's "Spreading the American Dream," RN - Nixon's Memoirs, NSC 162/2, effectively any book by John Lewis Gaddis, and I can go on for days giving citations or references but I think at this point I'd like to actually answer your question.

I'm going to go very quickly over very dense and interesting (to me) areas and time periods.

Well before the Cold War started, the United States in particular developed a deep-seated fear of Communism, the first Red Scare was well over twenty years before most historians would argue that the Cold War even started (though Gaddis puts the Cold War's beginnings in 1941). It's important to keep in mind that after the First World War, the U.S., while far from lovey dovey with the Soviet Union, wasn't particularly antagonistic, Harriman even tried to operate a (manganese?) mine there. But the inherent fear of Communism as an ideology never really left as a dominant stream.

Fast forward to 1945 and you have Truman and a cabinet mostly filled with anti-Soviets, though not all. (Again I'm pointing out I'm zooming through this). Kennan sends a telegram which effectively states that the Soviets have such an ideological twist to their worldview that the only real way to deal with them until they change is by preparing to contain them. Kennan never really, even over the years, defined exactly what he came to mean by containment, which allowed people like Paul Nitze to make it mean what it became - military, economic, and cultural containment on a global scale (rather than Kennan's strongpoint defence). Despite the fact that Kennan's arguments were also clearly shaped by ideology too, he, and others (Hans Morgenthau, Henry Kissinger etc.) argued they were espousing a Realistic position for American foreign policy.

To make a long long long story short, even in its initial phases, the fight against the Soviets and Communism was incredibly ideologically and morally motivated, from the top to the bottom. Truman loathed Communism, Eisenhower's cabinet as literally filled with people who hated the Soviets and communism on an ideological and nearly religious level, and so on. Eisenhower might not have been as ideologically committed to the idea, but even he had moral motivations, and anyone analysing his policies is forced to acknowledge that he took very many actions which had very little strategic value.

I can go on if you like, but it would be incorrect to argue that strategic reasons were really ever the prime motivators for American anti-communist policy in the Cold War, the closest this came to being correct was under Nixon.