Why was president truman considered to be weak on communism despite the federal governments measures to investigate communists

Truman was considered to be weak on communism because the Fear of communism had reached the level that bordered on hysteria , and Truman's action did little to make it goes away. 

This created a massive doubt within the mass about Truman seriousness in handling the Communism

To be honest i thinks its between the first answer and the third answer