Its a ponzi because of how exchanges work. The exchange takes your money, gives it to some of the early dropouts. When you sell for a loss, you've been lied to about the utility of bitcoin.

You likely never used bitcoin for any of the many advertised functions. You held it, and sold for a loss. Some will win, more will lose. Its a concentration of wealth with a little more class chaos than normal because it's accessible to a more diverse crowd. It still ultimately fails to incentivize useful work to society and it's still going to cause wealth to concentrate in the wrong direction.