Scare campaigns typically have something other than public safety and awareness behind them, and the end result of the campaign rarely justifies the means.
When McCarthy decided to go after the commies among us with his ridiculous Red witch hunt he was doing it for his own benefit, not the country's, and the source of his power over the American people was his "list" of Communists that had infiltrated the U.S. government.
This list is what he used to strike fear into the hearts of the American people, it started the Red Scare and served as the source of McCarthy's power- only this Red list didn't exist:
At first, McCarthy claimed that he had a list of 57 secret commies. Then it was 81, and at one point it was 10, which probably meant a bunch of them watched some John Wayne movies and changed their minds. Each time, the numbers would change, and each time, the senator flashed a piece of paper that contained the names of exactly zero Soviet subversives. It was the xenophobic fearmongering equivalent of saying you have a girlfriend in Canada.
John F. Kennedy similarly used the Red Scare to convince America to vote for him in the 1960 presidential election, claiming Dwight Eisenhower's negligence had allowed Russia to stockpile more missiles than the U.S., the so-called "missile gap":
We know now this claim was utter BS- U-2 spy planes had already determined the Russians couldn't reach the U.S. with their ICBMs or bombers, and America had already amassed a much larger arsenal.
But JFK knew the Republicans couldn't call his bluff without revealing the existence of secret spy plane missions against the Soviets, so Kennedy tossed out a ripe lie and America ate it up.