Thank you!

Thanks, get it now.
So, Elon doesnt know this and thinks that multiple uses of SSN is a proof of a fraud when in reality it is just a sign for a bad system that is not used as intended or not designed as it is needed?

Thanks for (starting to) explain this concept to people not accustomed to how the US does their shit.

See, where i live, we used to have for example a Tax-Number. That was a thing the taxdepartment used to identify a person. But if you move from city a to city b, that numbers changes. So if you move a lot, you will have numerous of these.
Now, some 15 years back, the Tax-ID was introduced (fellow residents at this point will lnow it might be Germany) and this number is a one-in-a-kind ID that will only be assigned to you. They create it shortly after birth. My sons first registraion ID was this, before anyrhing else. You will also get a uniqie healthcare-ID that also works like that.

So…how does that work in the US and why is habing a changing number that is not unique helpful? Or what is Elon not getting? I dont get it either because I dont know how this works for you.

Thanks in advance to shed light on this.