Most people are openly taught about the misdeeds of the McCarthy era in schools and in public discussions. This wasn't swept under the rug, most people agree that it happened and wasn't a good thing.
Learning "censorship is unAmerican, here's an example of how we tried it once and it was really bad so we ended it" is the definition of sweeping the nuanced reality of speech battles in the US under the carpet in favour of the free speech version of American exceptionalist myths.