Don't you love English. The langauge where polar opposites "sucks" and "blows" can mean in the right context exactly the same thing.

Surely you're joking, right? I've never encountered those two phrases where they meant the same thing.

Couldn't care less - absolute zero care. Nothing can disappoint me whatever happen. Could care less - some degree of care is present. Thing can actually get worse

Only if you've been around people who say it a lot and have the cultural context.

The internet, and Hacker News, is not that place.

There are plenty of people on here who will read "could" and "couldn't" as the actual words they are rather than the phrase they're a part of.