This question is asking for an overall judgment. A number of factors must be examined in order to explore the question in an analytical form. In order to get to the higher level, you need to produce a sustained analytical answer with a good structure. The argument must skillfully use evidence and include evaluation of this evidence.
The penetration by Soviet spies in the USA can be used as an example of a genuine threat to the USA. In 1941 there were 221 Soviet agents in the USA reporting back to the Red Army. An example can be used to support this and this would be the Rosenberg case. It could be argued that this led further to the development of the nuclear bomb and thus the ensuing arms race. Roosevelt's apparent over relaxed attitude to the degree of Soviet penetration can be offered as an argument as to why the threat intensified. The loss of China to communism may also be argued as a real threat to the USA. The loss was blamed on weak minded individuals by the right-wing press thus showing that there was a perceived threat at home. In terms of the sheer brutality and the creation of human misery, it is worth remembering that there was little to chose between of the Soviet regime and that of Hitler and in regards to foreign policy it needed treating with extreme suspicion. And so, the likeness of Stalin to Hitler meant a breaking down of the wartime alliance and a very real threat. Another aspect that is being flagged by the question to be explored relates to self-individuals. McCarhthy used the Red Scare to raise his profile through many witch-hunts. McCarthy was able to seize anti-communist sentiment to promote his career. Thus McCarthy manipulated the threat posed for his own political purposes. Furthermore, J. Edgar Hoover used the threat of communism to maintain his status in government. Hearst may also be explored as he was responsible for fuelling the hysteria surrounding the fear of communism through the media. And so it may be argued that these self-seeking individuals propelled a fear but there was no immediate threat.