You don't have to invest to ponzis.... you're not forcing to.... but please don't tell people that they don't earn investing to ponzis because they do earn.
And yes it's a risk, like any other investment is.
Ponzi schemes are stealing by lying.
If you put money in a Ponzi knowingly, you are helping the thief. You don't "earn" money, you steal it from later "investors".
On balance, the only people to make money from Ponzis are the admins.