Banks are in the business of intermediating: getting buyers and sellers of risks together. Today's banks do a lot of that as well. For example, they originate loans to consumers and sell those loans to investors. In that process, consumers get inexpensive loans (than otherwise possible) and investors get paid for taking risks.
That's how it
used to work under Glass-Steagall. Since its repeal in the late 1990s those lines no longer exist. The large majority of consumer loans are made by the big banks who also directly invest, speculate and take highly leveraged risks. That is - after all - what the 2007-2008 crisis was all about.
What happens in debt-driven societies, unfortunately for the banks, is that lots of consumers overestimated their ability to pay and see a larger and larger chunk of their income going to the banks (then going to the investors).
The truth is that banks benefit from a debt driven society - and in fact would not exist in their present form without a debt driven monetary and financial system - as all modern systems are (for better or worse).
In the US, the entire fractional reserve banking system (and with it government and consumer debt) has expanded enormously beginning with Nixon's closing of the "gold window" in 1971 then picking up speed with the 1980s deregulation of consumer banking and then reaching critical velocity with repeal of Glass - Steagal in the late 1990s..
This enabled both a major expansion of both government and consumer debt in a "borrow and spend" binge which allowed expansion of GDP without commensurate expansion of real wealth. The 07-08 crisis was the start of the chickens coming home to roost (round 2 to start in 1,2,3..) Since then all stops are being pulled out to prevent the party from ending and get consumers to resume the borrow and spend binge. (As if more of the same thing will fix the problem..
) Goverment - alas - has had no problem continuing its borrow and spending binge.
Being stupid, those consumers resent the banks for (having made a loan to them and) insisting on getting paid, on behalf of the investors.
What consumers actually resent is the banks taking leveraged risks with their money - then being bailed out by the government when their bets went wrong.(and that resentment is something both Trump and Sanders are benefiting from). In fact it was the bond holders who insisted on getting paid.
I think you will find a significant deterioration of standards of living in most western countries (Germany and Japan may be the exceptions) if the banking industry is as severely regulated as Ms. Warren had wanted.
In actual fact - the most prosperous period in history for the USA was the period under Glass -Steagall which is essentially what Warren would like to reinstate.
To me, killing the banks is one of those examples where its advocates are too stupid to know that they are killing themselves as well.
Based on what you've posted, I'd suggest more education about the financial system and its history before you call others stupid.
There's lots of room for honest debate about what the best parameters should be for a financial system that will allow a sustainable, prosperous society. In the Keynes versus Hayek debate, I decidedly lean towards the Hayek - Austrian school of thought but that does not mean I think Keynesians are stupid.
Similarly there can be honest debate about how much regulation of the banking system is healthy - and as in most things - either extreme is likely wrong.