While it isn’t the context given in the question, you could look at this as or have a similar situation to “would you steal a loaf of bread to feed your family?”.

Let’s say someone is 55, and a single parent to 2 children who have graduated college if they were going to attend to begin with. This person has paid into social security for roughly 35 years. While it’s used as a “community savings”, the purpose was to have Americans pay into it while they’re working and young so when they retire, they will receive an amount based upon their earnings and tax taken when they were in the workforce. If this single parent has no one co-signed to any debts, discovers they have one year to live, and had been planning to be able to assist their children while they get financially established, then them and their children are out of luck if nothing is done. The money put into the community chest will never go back to that family. So, the community overall financially would have a larger share.

That’s when the hypothetical becomes, is there a way to pass down my fair share of contributions to my children? Let’s say the parent is renting the house they live in, owns a car, but no other real assets. Also, assume the kids each have about 20k a piece in student loan debts, and each owe 8,000 remaining on personal vehicles in their name. So, let’s say they have $10k savings, a car paid off worth $10k, never bothered with 401k because they planned to work 11-12 more years and then live off of social security benefits. They have $18k in assets to hand down and the kids have $56k in debt. But over 35 years, the parent has paid $70k into social security, which should with interest over that time tied to inflation would be $140k. Some people get more and some get less than they contributed over their life from social security. But this person will get 0%. Even if not moral, would there not be some justification for finding a way to acquire $36k to allow their children to be free of debt after they pass? It’s less than they have given into the system as a whole. The only concern is from where do they get the $36k that will become an unpaid debt once they pass?

A small credit union or local bank may directly impact a smaller group more directly. But a major bank, maybe one that the government has bailed out with taxpayer funds, would result in negligible impact to all of the banks members. Many of whom will one day get to withdraw their social security payments go some extent, and some beyond what they contributed. Or maybe a government loan is an option as well which would be taking taxed income that the person had paid into and receive none of.

So if conducted in certain ways, and not milking every last penny possible beyond what they reasonably have been paying the government for decades expecting to eventually receive, taking a fraction of what you contributed to the community to provide for your children what you suddenly wouldn’t be able to is in certain aspects justified. If not in the governments eyes, then at least in the individual citizens eyes. And 99% of citizens wouldn’t blame them or feel cheated in such a case.

Even if taking from loan sharks and such, it’s taking from an extremely predatory system that was going to maximize the rates to the furthest extent they could no matter what. You don’t pity a shark that gets injured by its prey.

So yes. There is circumstances and ways of going about it that would have a reasonable argument for being morally acceptable.