True...and I think the latter, derogatory connotation is more inferred than implied. There is no sure-fire defense against the perceptions of the perverted.
I noted from the article that the "I can't...I'm Mormon" slogan started because the creator was tired of explaining why he wouldn't drink alcohol. My answer to such situations was very simple, "None for me, thanks. I've had enough."
Are you aware this implies you have already been drinking?