Is ransom payment even considered "stolen" in the usual sense? You have willingly paid that, nobody took that from you without permission. I wouldn't be surprised if ransom has it's own different definition.
Forcing an innocent to hand over bitcoins they had no clue they were tainted will make everyone lose trust in bitcoin and cryptocurrencies in general. What's the point of anonymity when trading when you're culpable for wherever that currency came from.
A quick test for "willingly" as you put it, is not due to force, fraud, or fear.
I would think that a ransom situation would likely qualify as some type of duress. Deciding whether the criminal act is "theft" (ie. stolen) or "fraud" or something else is probably missing the point.
And certainly, some aspect in the exchange (pay money for this encryption key) did not involve permission: the encryption of the files!
But, how to restore things after a wrong has occurred? I agree with your point that there is a risk of committing a greater wrong against an innocent party. Hence the special protections of currency as a unique type of property in the article. Does bitcoin fit this model? An interesting discussion!
For large amounts such as this one IMHO the key issue is that the recipient can be questioned about the source of the BTC - are they themselves related to the actual crime in question? And searched for evidence of the same.
If they're innocent, they will generally be able to identify the counterparty to whom they sold the goods or services valued at close to $1M, and the goods&services may then lead to the culprit; because (here's the thing) if they "just" did a fully anonymous $1M cash or cash-equivalent transaction, then they're not really innocent in many jurisdictions, because for large amounts money laundering laws generally (nuances depend on country) require you to identify the other party or not do it. Selling something anonymously for $10 in cash is innocent, but selling something intentionally anonymously for $1M in cash (or BTC) generally is a crime of money laundering by itself, no matter where the money came from.
The original article assumes (with no grounding, but just as an example) that the 'innocent recipient' might be some over-the-counter broker. That broker is legally required to 'know your customer'. And if they don't know their customers, well, then they're not innocent and deserve to lose their money.
The same applies to Bitfinex itself - they're required to know from whom they got these 96 BTC. If they don't, well, it's their problem, why not fine them the equivalent of 96 BTC or more for that.
Does a mugger steal anything? You "willingly" hand them your wallet. In the cryptolocker case, it is to recover your locked file. In the mugger case, it is to not get stabbed.
"Forcing an innocent to hand over bitcoins they had no clue they were tainted" shouldn't wreck trust in cryptocurrencies, but rather in the organization unjustly harming those innocents—i.e. the government. If anything the fact that they had to track down each individual recipient and force them to transfer the funds, rather than simply pressuring some bank or other intermediary, ought to increase trust in cryptocurrencies.
The "but I didn't know" excuse of innocence is not universal. In some cases one is required to do due diligence or risk catching some of the guilt in one's trades. Whether Bitcoin traders should be held responsible for the provenance of their coins is an interesting question. It really comes down to whether we want to protect Bitcoin as a payment system. And few people even care so it's not looking good.
Due diligence is not sufficient in the interesting cases. If exchanges instituted a blacklist of known ransom payments, for example, ransomware authors would just wait until the coins have been changed into some other untraceable form before releasing their hostages. Blacklisting the transaction in time to do any good would be the same as not paying the ransom. Reporting the address after the fact can only harm innocents several stages removed from the ransomers who could not possibly have known that the transaction was tainted.
The only reasonable solution is to track down the actual ransomers and make them pay for the damage they caused. Dragging other parties into this can only make things worse.
Making the receiving parties intent in covering losses can help a lot during discovery. Dragging "innocents" into it might just get us to a system that makes it hard for extortionists. And that system might not look like the Bitcoin we know.
You can argue that we should suffer the extortionists for other benefits we get out of Bitcoin. I'm not convinced at this point.
> Dragging "innocents" into it might just get us to a system that makes it hard for extortionists.
If you're willing to harm innocents for the sake of your cause—even if the goal is to make things harder for extortionists—then you're no better than those you're fighting.
I see this as an example where the ends can justify the means. The maximum loss those people could incur would be the sums exchanged. If those are restored to the damaged party I don't see how there's a good reason to protect the people who traded. They can still demand restoration from their partners after all. If they traded with crooks, they might get nothing back. Such is life.
To say this is the moral equivalence of extortion is a long shot.
Forcing an innocent to hand over bitcoins they had no clue they were tainted will make everyone lose trust in bitcoin and cryptocurrencies in general. What's the point of anonymity when trading when you're culpable for wherever that currency came from.