[DickingAround]

It seems fair to call someone a liar if you know they've said something factually untrue. (I'm no weighing in on the debate itself, but it's possible for someone to be factually wrong and it's appropriate to highlight that when it happens.)

[eropple]

You can be correct in the face of untruth and still be shitty and defensive about something; remember that Reddit storm when the CEO beefed with a fired employee?

I'm somewhat doubting that MCRed is lying, because he has some credibility to me through a history of good and productive posting, but it's possible.