How have the communism gotten such a bad reputation over in the US.

Because, as an economic system, it's the opposite of what our US capitalist ideology strives for. And our government and media have, for many years, done a good job of feeding us with the propoganda that their system was a threat to ours. I assume because they want to encourage the capitalist ideology.

There are, however, many places in the US that support communist thinking if not the specific communist system of another coutry. Small groups such as communes and co-ops operate as little "cells" of pseudo-communism floating in a capitalist sea.