Ahhhh!!! Communists!!

J. EDGAR HOOVER, “SPEECH BEFORE THE HOUSE COMMITTEE ON UN-AMERICAN ACTIVITIES” (26 MARCH 1947)

Note: J. Edgar Hoover was the head of the FBI at this time. 

'The communists have been, still are, and always will be a menace to freedom, to democratic ideals, to the worship of God, and to America’s way of life. I feel that once public opinion is thoroughly aroused as it is today, the fight against communism is well on its way. Victory will be assured once communists are identified and exposed because the public will take the first step of quarantining them so they can do no harm. Communism, in reality, is not a political party. It is a way of life–an evil and malignant way of life. It reveals a condition akin to disease that spreads like an epidemic; and like an epidemic, a quarantine is necessary to keep it from infecting the nation.'

Questions to answer: 
What was so offensive to Americans about Communism as a political ideology?
What was the purpose of the 'House Committe on Un-American Activities' - who were the targets of this committee?
Why would many people consider the committee itself to be 'Un-American'?