Joe Wilson said it:
But Obama kinda did too. And this — "a lie, plain and simple" — came before Joe Wilson's "you lie":
Obviously, Obama was the official speaker, and it's rude to yell something at the speaker. But Obama was guilty of disrespecting his critics by labeling their arguments nothing but a lie and — after getting a standing ovation for it — moving on.
Wilson's little outburst got a lot of attention, and that has lessened the amount of discussion of the actual content of Obama's speech itself. But I suppose that Obama supporters are using it to try to paint all the critics of the proposed legislation as louts to be dismissed out of hand.