It’s a tax. You could describe any beneficiaries of a tax in the same manner; we’re paying taxes to at least partially cover group X - homeless, scientists, military, retirees, veterans, etc.

There’s no debt being paid; money is simply taken from Peter, and money is simply given to Paul.

It’s not a retirement program, it’s retirement subsidization.

I don't think I'm willing to grant you Social Security as a proper "tax" or "subsidy" unless you're going to pitch me that Social Security is really, in essence, an incentive program for unrestrained natalism to keep population above replacement with all the Manifest Destiny/imperialistic implications and aspirations that come with it, and further, a commitment by the people who started it to never under any circumstances inform descendants of it's true nature.

If you are willing to concede the above, I'll reclassify it as a proper "subsidy" insomuch as it was a law that was passed, and it is a clear act by the government to incentivize activity "X". At which point my discussion will quickly turn to "Holy shit, why are we still trying to empire build in the year of our Lord 2025? Shouldn't we have changed this by now?"

If not... Still seeing it as a Ponzi. A fundamentally degenerate and unstable financial model, intended only to benefit the people who have been in it the longest solely for the purpose of self-enrichment. Well branded, mind; who doesn't want Social Security? But a Ponzi in essence nevertheless.

Without sufficient automation, all forms of retirement are inherently a Ponzi scheme, unless there is a cap to the age or amount of benefits received in retirement.