Only if you claimed you personally saw those millions celebrating when you only saw 12.
But if he did see a multitude, and you only heard about 12, it would be wrong for you to call him a liar.
It would be projecting. And that's what the Leftist media did; in fact, it is about the only thing a Leftist can reliably do. The skill is a requirement for being a Leftist in good standing.