On the internet , there are lots of people claming that the banking system has an immense power because it can multiply money obtained by deposits ( 'make money out of thin air' ) and then lend this money just with the provision of the reserve ratio , according to the theory of money multiplier.
They say that asking a real collateral for money without any previous existence is a fraud. It gives a disproportionate power to banks.
However, they seem not to consider that when the banks multiply money they gain a liability towards the depositor , and every time they multiply money is always a new liability due to deposits , so in the end the only profit for the banks ,say in a mortgage , should be the charged interest and not the entire mortgage (if the creation hadn't a liability it would be true) as they claim.
Are my considerations good? Can someone underline other relevant factors? Is this theory a total nonsense?