Why... Facebook is lying to (or misleading) its popular audience, not its advertisers.
How would they ever know unless a complete forensic audit takes place?? And since they Actively LIE to their subscribers why would it be a stretch of the imagination that they are also lying to their Advertisers FOR PROFIT OR GAIN??
Where there is smoke, there is usually fire, and I believe a few aggressive advertisers could really do some serious damage to the clown.