Yeah, I really have to stress I have no idea how any of this works so perhaps a roll-back for everyone that bought the fake MONA coins would work?
Probably not, it's been trading for a year so surely people have bought and sold and bought something else and withdrew etc... I doubt it could be untangled with a rollback. Livecoin really made in unnecessarily complicated by allowing a known bad coin/fork to be traded for so long.
I would argue that if you were buying MONA after the fact, you knew what you were getting yourself into (pure speculation since price was so much lower). Since there apparently was/is a market for it I don't think any of the users that currently trade it have lost anything. But I do agree with you, however nothing can be done about that now so I'm trying.
Some things also get lost in translation I feel which makes it increasingly more difficult. I'll keep people in here posted though.
If it was bought after the fact then
the exchange would have known that they were selling tokens that they did not have possession of. The buyer may not have had such knowledge. As soon as the exchange became aware of the issue they should have frozen the markets for that coin.
While an exchange is not responsible for the MONA network and 51% attacks are hard to detect in real time - the exchange should freeze the markets as soon as they become aware of a 51% attack or attacks.
Allowing trading to continue is effectively continuing to sell something that you know that you do not have.
Normally this would be a situation of he said vs she said, but in this case Livecoin has done SO MANY underhanded and shady things I have seen other failing exchanges do, that I have no question they are largely if not completely at fault here. As I explained before, I have personally witnessed this pattern of behavior from exchanges from the perspective of not just a user but a development team. They are struggling to find any lame half assed excuse they can to cover their asses just a little bit longer. There are no reasonable justifications for these repeated failures which clearly demonstrate negligence if not active fraud. They started making a bunch of money, started getting self assured and sloppy, and didn't put any of it back into security. Now they want to blame everyone under the sun. There is no way this exchange is not insolvent, because if it wasn't they wouldn't be actively cutting their own throats by acting like this.