Saying something you believe to be true isn't a lie, even if more information later makes you change your mind. You are expecting a level of perfection that just doesn't exist.
I believe Fauci knew enough to know that herd immunity wasn’t a real probability when he was on the news talking it up as the way we “return to normalcy”. Will there ever be a public trial to disprove my belief and vindicate what seem like glaring mistakes as honest scientific naivety rather than misguided public health messaging strategy? Maybe. But it seems few are interested in the actual historical facts and would rather let sleeping dogs lie, bygones be bygones, since it’s all water under the bridge anyway and we have new things to fear like book banning and transgender athletes and Tucker platforming people who think Macron’s wife’s a dude. I’m inclined instead to believe knowledge is power, history repeats itself and governments should be transparent and accountable, even if it means putting our kings on trial.