Whether they had enough money paid out through dividends in the run-up to that point or not is situation dependent - the company could not pay dividends at all.

That's just part of the risk. We're now talking about the bill that is still on the table. If the "investors" were fully responsible for their "investments" they would not have worthless shares, but they would have to pay up for what the company still owes. That their risk stops at "shares being worthless" is exactly what I mean by them being shielded.

I learned the energy firm was a coop: they have no shareholders.

But the discussion is still interesting, well at least to me :)

Hence, anything that has real costs higher than their invested stake has effective costs for them at their invested stake. They are shielded to some extent. Especially for low probability high cost events.

This is exactly the point of a limited liability company, but it comes with slightly perverse incentives.

With limited liability the investors are never liable for the debts. That's exactly how limited liability shields investors.

Yes, assuming you meant "shareholders" rather than "investors"—creditors are also investors, having put money into the company with the expectation of a return, but would not be liable for borrowers' debts regardless of limited liability. It's the shareholders who are shielded from liability to the corporation's creditors. But the creditors know this and accept the risk as a cost of doing business with a limited liability corporation. If they don't like the corporation's prospects they are not obligated to extend credit.