Personally, I don't have too much problem with sigs like that, it's clearly marked HYIP which anyone with the slightest idea knows means Ponzi.
HYIP is just a name the industry made up.
The site Rob It Bot  (the clue's in the name) only makes a half hearted attempt to pretend they are anything but a last in loses Ponzi type scheme.
There has got to be some Caveat Emptor somewhere, anyone going into that would probably have their eyes open.

What I think should be negatived are schemes like the one in my homemade sig, which blatantly lie and pretend to be legitimate, forex dealing, arbitrage, cloudminers etc.
That's why the CloudThink signature campaign raised a lot of criticism of senior + members who signed up for it, it so obviously screamed scam while pretending to be legit, but they still queued up to take the money.
I personally think that established forum members have a duty to research what they advertise and if there is a major red flag, err on the side of caution and decide against helping pretty likely scammers (although not proven to legal standards maybe) with their deception.