Divisor in the sense of greatest common divisor is not the same as a denominator. More to the point, we may indeed care about greatest common divisors, but we also care about least common denominators (i.e. least common multiples)
"could care less" is a mistake that just grew popular enough to become common use; it doesn't make any sense as a statement since it implies that you haven't hit your care 'floor'.
This may be a bitter pill to swallow, but silly and meaningless idioms are a dime a dozen. When push comes to shove, it's not something worth losing your cool over.
Perhaps they're a dime-a-dozen because they go unchallenged?
I've had junior members of staff express genuine surprise when I've corrected such mistakes in documents. It's a difficult thing to do without offense, but when clear meaning is imperative there's no leeway for doubt.
In 20 years time, will people still understand today's silly idioms or try to read them literally? "Nip it in the butt!"
Don't worry, I wasn't mashing my fingers into my keyboard in a sweaty rage while typing the above. Life is full of little annoyances, some are fun to comment on though.
Let someone who is pedantic about language, be pedantic. It's not like this is a feature unique to the reddit user base, it abounds on all corners of the internet.
I usually send personal messages when I see this particular error. That's not possible on HN, so I guess a comment is the next best thing. Your downvotes, however, tell me we should just get used to seeing it "could care less" more often.
It isn't an error, unless you think language has to be perfectly regular and logical with no warts. That's a fantasy. Language develops organically and as such we should expect contradictions and illogical constructions to arise from time to time.
Everyone knows what "could care less" means. There's no external, objective standard by which you can say it's "incorrect". Stop worrying about it.
An example of this type of inversion that has become widespread: in French, "pas" means "not", but originally meant "step", and came into its current meaning via (roughly) the following sequence:
"Je ne marche" (I don't walk) -> "Je ne marche pas" (something like: I don't walk [even a single] step) -> "Je marche pas" (over time, "ne" became dropped in informal speech, and "pas" carries the negative meaning.)
Yep, and constructions like "il ne dit mot", "il ne boit goutte", etc., were once much more common than they are today. Not sure why "pas" became the canonical negation word out of all those choices.