It's really not. A ponzi scheme is an investment scam that pretends you can profit while actually your money is being used to scam other people. And the money obviously ends up going to the guy running the scam.
Social security is a type of national insurance. We all pay a bit into the pot which is then distributed to those who need it. Maybe you'll need unemployment for a while, maybe you'll need care when you're older, maybe you're lucky enough that you'll never need anything. But it's a social safety net for all of us.
And yes most of us don't need it right now, so clever morons like Musk can spin it into "why am I paying for this other guy's unemployment?" That is the real scam, to break our willingness to lend a hand to our neighbors and often to ourselves.
That was my thought in the first two panels but the last two seem to reverse that. But hell I probably already put way more thought into it than I needed to already.