If lying violated the TOU, the IHoosgow would be the most overcrowded correctional facility the world has ever seen.
"...but nobody can mention it?" It is the word "lie" that is problematic. Lying is a word imputing dishonesty; its definition includes the intent to deceive, and a poster's intent is considered off topic.
So you can say "that is a completely false statement," you just can't say "that is intentionally a completely false statement," i.e. -- a lie.