If a bank gets hacked, generally the transactions get reversed. If a cryptocurrency exchange gets hacked, that generally can't be reversed.
Regulation can make things more secure, but I don't think it can realistically stop all attacks. Regulation is slower than attackers. The ability to reverse transactions is what's really needed to prevent attackers from getting away with money.
Who will be in charge of deciding which transactions need to be reversed and when? It seems to me that the ability to have reversible transactions is at odds with the descentralised nature of blockchains.
I agree with you. There doesn't seem to be a good way to allow transactions to be reversed while keeping decentralization.
My point is that this decentralization is bringing in a risk that traditional banks don't have. So saying "regulating it like a bank will make it as secure as a bank" is incorrect.
Regulation can make things more secure, but I don't think it can realistically stop all attacks. Regulation is slower than attackers. The ability to reverse transactions is what's really needed to prevent attackers from getting away with money.