That's a different issue altogether. I'm not going to debate the anti-tobacco lobbies blowing it out of proportion, as that is obvious. AFAIK, stress is much worse for your sex life than tobacco.
Alcohol is known to be actually good for sex in small to moderate amounts, and devastating in large amounts (too much booze and you won't be able to, even if you want). But alcohol it isn't the target of a "holier-than-thou" social crusade, so that's beside the point.
However, the original statement was "Smoking is bad for your sex life", which holds true. Nicotin is a vasoconstrictor, which if combined with other vasoconstrictors, stress or other unfavorable circumstances can result in erectile dysfunction. Granted, tobacco will hardly make you impotent by itself, but it's bad anyway.