You're pissing into the wind. Saying "I could care less" as a sarcastic way to express that you don't care at all is certainly wrong, but you'll never change those who stubbornly insist on using it.
It's like trying to correct those who pronounce the "t" in "often", which is also technically WRONG! But that has become so widely accepted now, that even those people who know better and used to overlook it either as an affectation or as an over-correction (i.e. used by the less intelligent to tacitly demonstrate that they are not lazy speakers and/or know how to spell the word "often") are beginning to adopt the wrong pronunciation themselves so as not to appear "stupid".
Of course, no one who says "often" pronouncing the "t" will pronounce the "t" in the words "soften", "fasten", "hasten" or "listen". But pointing this out has become a similar situation of relieving yourself into a strong breeze. You'll never convince those who do it to change.
Will "could care less" eventually become accepted as proper idiomatic English meaning the same as "couldn't care less"? It's not as far along as the pronounced "t" in "often", but it's almost there. You might as well begin accepting it. :lol:
