Answer
This quote means that we are to blame for what happened. What Murrow is saying is that we are to blame for the spread of McCarthyism. On his own, Joseph McCarthy's ideas would not have taken hold, but since the people were in fear during the Red Scare, they rallied behind this man to try and fight against the thing they were afraid of. Thus, McCarthyism spread, and the people are at fault for it.
Step-by-step explanation: