..if we are told that we'd be responsible for all loses we would change our behaviour: we'd stop using banks and credit cards.
I'm sure Hogan-Howe is a nice chap but he lives in a world where we are perceived to be the problem and his words reflect that. Having people be better computers is not a solution to anything. History shows we are incapable of being more secure. Even those who are conscientious will fail some time.
Clearly the banks don't want us to walk away. Perhaps the other side of the story was not covered by Hogan-Howe or not so newsworthy. The other side is that banks also have options. One is to make it impossible for our accounts to be hacked or used fraudulently. However this is, at the moment, prohibitively expensive. It's much cheaper to have the actuaries work out the cost of fraud and set the cost against profits like any other business expense such as marketing or accounting. So that's the status quo. It exists not because we are all evil (stupid maybe) but because its the least expensive option that is also reliable and managable.