A calculated risk is that you put money into something which may end up losing all of its value; not that your collateral becomes locked in a safe with an accidentally lost key. They had a reasonable expectation that even if the value was totally lost, they wouldn't have their collateral locked forever. Their investment, yes, but not their collateral.
Sure, one always has to account for extreme scenarios when doing anything, like the risk of a critical flaw in the code. But to give another extreme gambling scenario:
Let's say you put your car up as collateral for a huge gambling bet. You of course take a calculated risk that if you lose the bet, you lose your car. Then let's say you back out of the bet after putting up the collateral, or you even win the bet, but there was a mixup at the casino and they thought you lost the bet and they took your car without you realizing it and it's on another continent now.
In both scenarios, you hope that you can at least get some kind of compensation from the people you entrusted the collateral to, since it was just a complete fuckup on their part. You know you're not guaranteed to get anything, but I think it's reasonable to try to ask for compensation. If you just took a bet and the value plummeted, then you know it's tough luck for you and just a standard high-risk high-reward scenario that you ended up on the losing side of, but this is something else.
(At least if I'm understanding this properly and the collateral really was purely collateral. Seems to be a bit complicated because they were attempting to make a... stablecoin... pegged to an intentionally volatile asset, somehow.)
>This is exactly what crypto-enthusiasts claim is going to happen to the US Dollar
It's mostly just Bitcoin maximalists who think that, and they're a small subset of people who own Bitcoin. This is Binance Smart Chain (basically a copy of Ethereum), and I'm sure some BSC/Ethereum users believe something similar, but it's a much smaller percentage than even Bitcoin's small percentage.
Also, I don't think they think every dollar is secretly embedded with nanobots that'll encase the bill in titanium after someone at the Fed trips and falls on a big red button, which is what would be analogous to this. I think they think the dollar will lose most or all of its value due to hyperinflation. I think that's a completely unfounded belief based on an unfounded philosophy, but it's a different and entirely unrelated thing.