HYIP abusing - Is there something like morally unacceptable profit?

I've been reading a lot about HYIPs (High Yield Interest Programs) lately - for those of you who have been living under a rock: bitconnect, chaingroup and all those that promise incredible daily returns. I am fully aware that they are ponzi schemes and unsustainable in the long (or some even short) term.

BUT ...

There are some strategies out there that are heavily abusing theses HYIPs - rigorous vetting, getting in early, withdrawing you investment asap and then snowballing the "free" money. More details here, if you are interested: http://hyip-rotation-system.com/

So as long as the owner of the ponzi is not totally incompetent and manages to at least add one or two layers to his pyramid system, this honestly seems pretty low risk. But compared to the "normal" ponzi investor, you are fully aware that this is turing into a scam sooner or later and that your (potential) profits are solely based on other peoples (future) losses. Compare that to the traditional, dumb ponzi investor who wholeheartedly believes that there is some sort of magic trading bot that will make everyone millionaires.

Investing into a ponzi is obviously perfectly legal - even when you intend to abuse the system. But is it ethical? Is there something like morally unacceptable profit? Or is this just a consequence of a free market system?

I'm curious to hear your opinions about this.
Some fuel for the discussion:

• Are you invested in any HYIPs?
• If so: Do you believe in their claims (profits made from a trading bot)?
• Should investing in Ponzi Schemes be illegal?
• What about actively advertising them / spreading referrer links?