I could care less (this one is everywhere)
I've posted this little philosophy elsewhere so forgive me if you've already ready it.
I could care less is actually more honest and more accurate if you want to be pedantic. If you care enough about something to post a comment then you do care somewhat and could in fact care less. Stating that you could not care less about something when you actually could care less is a falsehood.
First, you're working backward instead of forward.
To simply comment on something doesn't mean you care about it.
You're arguing from only the idea of the unsolicited comment. Often, "I could/n't care less" is a result of the question, "What do you think about that?"
In the case of a solicited response, "I could care less" allows for exactly that, less caring or interest or whatever.