In hindsight we know that red scare was as bad as the thing they were fighting against
As the Cold War intensified, the frenzy over the perceived threat posed by Communists in the U.S. became known as the Red Scare. The United States government responded by creating the House Un-American Activities Committee (HUAC), which was charged with identifying Communist threats to the United States. HUAC often pressured witnesses to surrender names and other information that could lead to the apprehension of Communists and Communist sympathizers. Committee members branded witnesses as “red” if they refused to comply or hesitated in answering committee questions.
with the only exception that Americans could not flee from persecutions.
"As bad as" is doing a lot of glossing over things there. HUAC and McCarthyism were reprehensible. That doesn't mean they were equivalent to abuses that occurred in the Soviet Union.
As the Cold War intensified, the frenzy over the perceived threat posed by Communists in the U.S. became known as the Red Scare. The United States government responded by creating the House Un-American Activities Committee (HUAC), which was charged with identifying Communist threats to the United States. HUAC often pressured witnesses to surrender names and other information that could lead to the apprehension of Communists and Communist sympathizers. Committee members branded witnesses as “red” if they refused to comply or hesitated in answering committee questions.
with the only exception that Americans could not flee from persecutions.