The word "lied" has a lot of layers[0] other than "knowingly said an outright falsehood". He may not have told an outright, provable falsehood (although some of these examples are close). He certainly has a long history of statements to Congress that are baldly misleading or belied by Meta's own internal records.

[0] https://en.wikipedia.org/wiki/Lie#Types_and_associated_terms