[captainmuon]

Well, but the vast majority is carrying the decision by following the fork / rollback, right? If just 5% of there network does the fork, shouldn't the 95% be able to continue with the old version (and the fork would become effectively worthless)? At least that's how it would work with bitcoin.

If the system allows 5% of users (or computing power) to make arbitrary changes, then that is the problem.

If I'm correctly informed, the cause was not a bad investment, but a bug/loophole in the contract that allowed people to steal etherium. (Of course you could take the code-legalistic position and say whatever the original code did, was the contract, even with bugs, and if people invested, they accepted these bugs as part of the agreement. But then I raise you this: the features of etherium that allow people to make changes to contracts are also part of the agreement! So if you say they shouldn't have invested in a buggy contact, tough luck, then I can say tough luck you invested in a malleble system :-))

If there was a bug (unexpected functionality) in the specification, then a certain quorum of users should be able to change the spec to match group expectations, even retroactively. I consider that to be a feature, not a bug.