The way it was done, Bitmain is guilty and must take the consequences for it. It's not fair that people suffer such astronomical damage as that. No doubt that Bitmain has responsibility for what happened...
No man, you didn't understand... how many times have you received an email from a BIG company (from their REAL servers), but was actually a fraud? If that were common and "acceptable", the email would have been extinguished a long time ago... The problem is not the email as vulnerable technology... many serious huge companies work every day with much more important data and money by email with their customers and partners. The problem is the lack of security on Bitmain servers! That's why Bitmain is guilty for that. If you had received an email from Nvidia's OFFICIAL email for example, with all your REAL data (including your address!!!) offering some kind of discount and you were fooled by it (again... coming from the OFFICIAL email with your REAL data)... the reason for this would have been purely a security breach of Nvidia and you can be sure that if you proved to have made the payment, they would take some action to reimburse you and everyone who was harmed. Any serious company would do that. If the email had been sent from another server, not from Bitmain's email server, then you would be right... But is NOT the case!