In America, communism has been considered a frightening concept. Do you understand why Americans reject communism or why it goes again America...

I agree with the basic idea of answer 1 and disagree with
the basic idea of answer 2.  The reason I say this is that I do not agree that Americans
feared communism because the politicians made us do it.  I do not believe that
anti-communism was a way of stifling dissent within the US
either.

I think that Americans have feared communism
because it (as practiced) takes away people's freedom.

As
the first answer says, communism certainly takes away people's freedom to get ahead
economically.  Communism as practiced has also stifled human rights in a way that is far
beyond anything that has been done in the US (outside of slavery).  People do not get
executed for dissent in democracies.  Democracies do not ban or try to control religion
either.

America is based on the idea of freedom even if we
do not live up to that ideal all the time.  Communism takes away many freedoms (at least
as it has been practiced in the real world).  This is why Americans have feared
it.