I think for some people the mathematics of Ponzi are just too counterintuitive so that they are not immediately obvious, even if they are able to understand the maths. They let their feelings of confidence and trust override their rational capabilities.
Greed? Or, to put it more politely, the intense wish to get rich quick.
It might be that if it seems hard to understand why some people think that something is definitely, without a doubt a ponzi, you need to think it through from a hypothetical scammer's perspective. It's actually very easy to run a ponzi scam (the hard thing is determining when to run with the money). The only thing that is needed is the tendency to let feelings override rationality. Many people who OUGHT TO HAVE KNOWN BETTER have been scammed. Being (susceptible for being) scammed is not the same as being stupid. No amount of intellect can save you if you let your feelings override it.
Very true. But the intensity of the rationalizations kept surprising me. (I don't tend to get emotional when dealing with money.)
Look at this discussion here. Even now, when we know for sure that the pirate ran a Ponzi scheme, somebody is arguing in the direction that it might not have been a Ponzi scheme. Seems rather ridiculous to me, but that is how our buggy brains sometimes work.
