im doing something from the cold war.. Why did americans fear communism?

Question

How did communism impact American society?

Answer 1

It wasn't fear so much...We tend to be on our toes when faced with regimes that would commit mass exterminations upon its own people ie. Stalin,Khmer Rouge,Mao...Kind of "if they do that to their own people,what would they do to us" mentality

Answer 2

mostly because countries which claimed to be communist did their best to anihilate the US - by disinformation, sabotage, espionnage, "proxy" wars and economic warfare.

for example- the US was cheated (via work of communist agents in mass media and State Department) into abandoning China to the communists- end effect was over 70 milion murdered chinese nationalists and a subsequent invasion of Tibet, a war in India, Korea and in Vietnam. I'd say that was reason enough to be scared.