STYLE IS AN OPTION. CLEAN IS NOT.
Surely that's not what Tide really wants to say? "X is not an option," in the language I speak, means X is not a possibility, X is totally unthinkable – as in the famous "Apollo 13" line, “Failure is not an option.”
I think the copywriters were trying to say that "clean is not optional" – that fashion is a choice, but cleanliness is mandatory (an article of faith, surely, among detergent manufacturers).
The “style” half of the tagline has its own problems. My first reading of “Style is an option” would be that you can choose to be stylish or unstylish; but that doesn’t make much sense in an ad focused on looking good. No, the writers seem to be using “style is an option” as shorthand for “your style is up to you." It isn’t exactly idiomatic English, but at least – unlike the second part of the tagline – it doesn’t say the opposite of what it means.
I guess the intent is so clear (that's what pictures are for) that it doesn't really matter what the tagline says. Or is this usage really changing? Time and Tide wait for no man, they say, and it could be they've left me in the dust.