LOL--great point! The proverb actually comes from 1 Corinthians 9:25, which actually says, "every man that striveth for the mastery is moderate in all things." The word "moderate" there actually means "self-controlled". But "self-control in everything" doesn't sound nearly as appealing. :-0
I think Saul of Tarsus was really onto something. I have actually had people challenge my refusal to smoke pot by using the "moderation in all things" argument.