That being said, calling these platforms "ponzis" isn't correct, the most you can say is that they were front ends for a ponzi. It would be like setting up a front-end to receive investments, and then depositing the money with Madoff. I'm not saying that it is a legitimate business, just not a ponzi.
And I'm not defending these companies either, a very light DD [2] made it obvious that the LUNA-UST mechanism was broken and the collapse was inevitable. It's really messed up that they put clients' money at risk, and that they lost it. I also think that YC is somewhat responsible for this.
What makes the situation even worse is that the collapse didn't happen from one day to the next, they actually had time to pull the money out at a 0.5%-5% loss, but they still decided to wait and see if it would repeg.
[0] https://twitter.com/josusanmartin/status/1478185473499615233
[1] https://twitter.com/josusanmartin/status/1478188494463848448
[2] This DD took me less than 1 hour: https://twitter.com/josusanmartin/status/1524323026942242818