Many countries require passports to be valid for at least 6 months in order to enter. That's just the way it is. So always make sure you have at least that.

The reason the carrier won't cut you any slack is because if they knowingly carry someone who will be denied entry, they will be responsible for returning you to your origin on the next flight when immigration denies entry (potentially even kicking another confirmed passenger off, if the flight is full) as well as subject to fines. I don't know of any carrier that would want to risk that, knowing that the passport isn't valid for entry. It's the same reason airlines check visas at check in and in some cases, boarding - they want to make sure all pax have the correct entry docs.

It is always the travelers responsibility to make sure they meet the eligibility requirements for entry into whatever county they will be visiting. And the airlines check that. You found out the hard way, unfortunately.

I have seen rare instances of fare rules allowing for a refund if documents are not granted. But only ex-India to the US, IIRC, and I think it was specifically for if a Visa was denied.