Where in the text of their comment did they say that?
The sentence you quoted doesn't have anything to do with the point you claimed they're making.
And the GP is right: banks have to lend because the system is set up to use credit for investment, personal consumption, and to balance shocks. Doesn't take anyone being altruistic.
They are propping up the world economy though. They're not sitting on top of their cash reserves like dragons and their hoards. They are "efficiently allocating the capital" by lending at interest. That's the number one cause of inflation. They make it so there's so much money circulating it slowly becomes worthless.
Someone needs a $1,000 loan. Bank issues it against some collateral. They grab the cash and spend it. Whoever receives that money deposits it at the bank. They keep $100 and loan $900 back out. It eventually gets deposited again. A significant fraction is loaned out again! Then it gets deposited again!! Then $1,000 turns into $100,000 literally overnight! Not one cent of it real until the loans are paid back, until somebody actually goes and extracts value from this planet! Exponential growth in a linear planet, it's unsustainable.
The entire global economy is leveraged this way! It's not real until the loans are paid back! If people start defaulting on these loans, it's fucking over. People depend on those payments in order to pay back their own loans. Defaults generate more defaults which generate even more defaults, like a society level stack unwinding. Next thing you know the government is "injecting liquidity" into banks. If they don't bail out the banks everything come crashing down.
We live in the age of CBDCs, of programmable currency. We have governments speaking of negative interest rates and expiring money to drive consumption. People have to keep consuming, they have to keep spending money. The motor of capitalism must keep turning. Otherwise the loans go unpaid and everybody gets liquidated.
Banks are altruistic actors who generously prop up the world economy by lending to non-creditworthy buyers? That's a new one for HN.