Knock it off. You can call his comments a lie, but avoid the personal attacks on him.
It's not a personal attack if what he's saying is a lie.
So say the post is a lie. Say it's bullshit. Don't call him a liar. I know it's semantics, but it could mean the difference between getting an infraction or not depending on the judgment of who's handing it out.
Besides which, the "Suck it up Nancy" part is pretty hard to defend.