There are two ways to take it, either as "I am so committed to my faith that I will not lower my standards." or as "I would love to lower my standards but my religion has more control over my life than I do."
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."
"I can't....I'm an aethist"
"I can't...I'm too liberal"
"I can't...I voted for Gore"
"I can't...the AFL-CIO hasn't told me how yet"
"I can't...My guru says it ruins my karma"
"I can't...my chakras aren't balanced"
"I can't...It makes me look like a liberal."
"I can't...under the protect of the Fifth Amendment"
"I can't...its not a legally controlling authority."
"I can't....Hillary won't let me"