"could care less"

THIS

"it means the same thing!" they say

IF COULD CARE LESS MEANS THE SAME AS COULD NOT CARE LESS THEN THE WORD "NOT" IS ENTIRELY MEANINGLESS

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA