Bzzt. Wrong. The saying means exactly what it says.
Would it be clearer to you if the saying was, "I suppose that I could care less."?
The claim is that it is possible to care less. The fact that you need to think about and say it indicates that that possibility is remote and unlikely. Of course I pointed this out to you before, but you didn't seem to get it then either.
I guess that someone out there could be stupid enough to find this kind of roundabout insult even more opaque than you do.
Ben