Why Hollywood ten go to prison?

The Hollywood Ten were a group of screenwriters and directors who were cited for contempt of Congress in 1947 after refusing to answer questions about their political beliefs and alleged communist affiliations during a House Un-American Activities Committee (HUAC) hearing. They invoked the First Amendment, arguing that their right to free speech was being violated. As a result, they were found guilty and sentenced to prison terms ranging from six months to a year. Their case became a significant event in the larger context of the Red Scare and the Hollywood blacklist era.