When we say we exhale carbon dioxide that doesn't take into account various other gasses we exhale either, include water vapor. Does that 1-2% make you a liar?
LOL! Well, if I said. "I exhale NOTHING but carbon dioxide" that would be a lie. If I said, "I exhale carbon dioxide" with the 'among other gasses' implied, that would be the truth.
So, if someone says "e-cig vapor is NOTHING but water vapor" that would not be true. "Mostly water vapor" would be more accurate. And I have seen people say that e-cig vapor is *nothing* but water vapor both here and in comments sections of articles about e-cigs and such.