I'm no legal expert, and I FIRMLY DISAGREE WITH THE THEFT OF FUNDS THAT WERE INITIATED BY THE HARD FORK. However, Exchanges are neutral third parties in this matter and are acting as a currency exchange - if you think in the terms of Fiat - where they take a currency (cryptocurrency instead of hard currency), and give you back a different currency (less a transaction fee). Accepting and converting a given currency is not accepting the political choices of that currency's authority. It's merely a choice of accepting the risk that the original currency has value and that the destination currency has value, and placing a value on the difficulty to transact in those currencies to come up with your fee.
Perhaps there is a Fiduciary responsibility? But at least in the US, this would not be the case today.
I know this isn't what we want to see or hear from a currency, and again, I'm not a legal expert (and this is not legal advice), but I can't imagine that accepting a hard fork is the same as becoming complicit with the fraud or other actions that occur within transactions that are unrelated to the transactions that are actually conducted by a currency exchange. That'd be similar to saying that every bank that holds USD is responsible for every USD Globally and any financial fraud or terrorism paid for by every US dollar is the fault of every bank that holds and transacts in USD.
Fiat currency exchanges don't have to run code that in this case implements theft. Crypto exchanges do.
If you run code that implements theft you may become implicated in that theft.
It is an acceptance of the code to run it.
The code that holds hostage the value that the crypto exchanges maintain as a means to conduct business. The code that the crypto exchanges run in order to continue business operations for all of their customers (not just the handful of illegally affected customers).
Again, I agree that the whole JS shenanigans are ridiculous and should be illegal (regardless of existing law by whatever jurisdiction), but you can't hold exchanges accountable for actions that they are "accepting" on behalf of the 10k+ users who are not negatively affected by this fraud. There are courts to settle the matters of "the few", while a hold-ups like this means that the majority are now being punished by the few.
It's no surprise that JS stole from some of the biggest accounts (full stop). The guy thought he was getting more value from Steem than he'll ever get, even after conducting this abhorrent confiscation of user funds.
Ned screwed everyone, and now JS continues the trend with the whales / witnesses who fought TRON and had any sort of stake to compete with him.
Everyone flipped when exchanges backed JS over the witnesses (that should have been a call to arms / illegal act / made witnesses de-list from the untrustworthy exchanges), now the same people want the exchanges to back the "old witnesses" over the acting witnesses who pushed the new code? ... so, trust the witnesses - but not the ones that are acting on behalf of the blockchain? It's a tough legal argument for me to chew..
Again, illegal, immoral, not something that should ever be done, and anti-blockchain ethos. But I am not seeing how this is the responsibility of the exchanges.