Communism represented an existential threat to western capitalistic, dmeocraticdemocratic societies; FasccismFascism, which started out as a "one country" thing, did not. If Italy, for instance, became fascist, that didn't mean that other countries would. As late as 1939, people like Neville Chamberlain thought that capitalist democracies could co-exist with Naziismthe Nazis. (Churchill did not.)
Few people thought the same about Communism. Its most disturbing feature was that it planned to "clone" itself in other countries, thereby creating a series of "national" revolutions that would add up to a world revolution. Either a national revolution in your country or a world revolution would be a disturbing thing to most people in power, and in fact, most people in most countries, unless you were already so downtrodden that the promise of any change spelled relief.
Unlike fascism, Communism preached government from tethe bottom up. That is, the dictatorship of the "proletariat," the workers in Russia, the peasants in China. Although the movement was led by middle class people like Lenin, it was not really in the interests of that group. A middle class person could not feel safe in a Communist regime supposedly run for the benefit of the proletariat, with the possible exceptions of Lenin, Stalin, and Mao. Forget
Worse, the capitalist class could sabotage the new nation by "going on strike," because they knew best how to maximize the value of productive resources. Forget, for a moment, about China and Russia, and the fact that their industries took years, even decades, to recover from numerous failed "experiments".Perhaps Perhaps the best example of this potential for collapse was Zimbabwe.