Initially, "I couldn't care less" indicated that the speaker cared so little, in fact not at all, that it would be impossible for them to care any less. This expression has morphed into its antithesis. We hear "I could care less" more frequently than its accurate predecessor, but it is used to mean the same thing.
It doesn't mean the same thing, and as I have continued to hear it and focus on the speaker's origin, emotion, tone, and situation, I've come to realize that it is indeed accurate.
They care. They are suffering. They want to care less but don't and need to figure out how.
And aren't we supposed to care? Isn't that what we are taught about being good humans? I spent most of my life caring about every little thing, and I'm here to tell you that caring less is an entirely valid path to peace and acceptance. I care about my small sphere and each direct connection I make. Beyond that, most things have nothing to do with me, and I couldn't care less.