It does suck for those who did transactions in that time, all those transaction did not occur now. This is in general not a big problem unless for example you used BTC to buy Grin. The buyer would not have received the Grin, but the seller would have received BTC.
No they should not, crypto is a decentralized system, not a bank. There is no one ‘responsible’ we all are. You and me are equally responsible for not spotting the bug as the developers are since we are our own banks we have our own responsibility. That is the price to pay for being part of decentralized financial system. Of course I think all parties involved will try to avoid as much people from having problems, but that is only out of idealism/kindness/choise, not because it is their responsibility.