Well, as a matter of fact, I would understand 'I could care less' when someone has been taken with something too much and realizes it. Obviously, it seems the OP's meaning was not this...
Yes, its irritating, like not using the apostrophe correctly :-)
"I could care less." - There is room for you to care less than you care now. This phrase is meaningless as a way to describe how much you care about something.