How ethical was the handling of alleged communists in the United States during the "Red Scare"?

The "Red Scare" was a time frame in United States history in the late 1940s and early 1950s which was marked by a strong fear of Russia and the threat of communist spies in the United States. As communism advanced throughout the world, many Americans feared it would take hold in the United States. In March 1947, President Truman issued an executive order, known as the Loyalty Order, which mandated that all federal employees be analyzed in order to determine whether they were sufficiently loyal to the US government. A House Un-American Activities Committee began investigating government employee sympathies with Russians and communist viewpoints. A spotlight was also shown on the Hollywood film industry. A "blacklist" of suspected communists was created and distributed, ruining many individual's careers. Senator McCarthy used the American fear of Russia to shut-down any of his opponents. He accused many who did not support his political views as communist sympathizers and spies.
This period in United States history saw a reduction in civil liberties and the freedom of speech. Individuals accused of supporting communism were alienated by their friends and family, terminated from their employment, and sometimes even harassed by law enforcement. Arthur Miller wrote the play The Crucible as a metaphor for the Red Scare, comparing it to the Salem Witch Trails.