Well, we do have a risk here of going wildly off-topic, but we can address it a little bit.
No idea, to be perfectly honest. I suppose we can compare this perhaps to a gambling addiction (or to some extent any other kind of addiction). Why do so many gamblers lose everything they have, and yet they keep going back, hoping to hit that jackpot again? Getting scammed is most likely not an addiction thing, but there do seem to be similarities nonetheless. This also does touch upon the idea of freewill (which is why I said we can go very far off-topic), and thus whether someone who has been scammed before and keeps on falling for scams is actively choosing to do so. I don't know.
None of us are in control of the chemical and/or electrical signals happening in our brains, and since those are the very things that control absolutely everything about how our bodies operate, it makes it very difficult to gauge whether any of us can really choose anything. So, does someone choose to get scammed again and again, do they not care, etc etc? I really dunno.
You see, it's easy for us to assume that someone who has been scammed would have learned a lesson. We assume it's the same as a child who might put their hand on a hot stove, get burned, and then never do it again. But I'm not so convinced that it's quite that simple.
As for the scammers...well, they clearly have no sense of morality and certainly no empathy. But again, are they in control of how they operate...are they really choosing to scam people over and over? I'm not sure.
But even if we don't truly have freewill, the fact is that Cheri & Co. are still an objective threat to the well-being of others, and therefore should be stopped.
What makes things worse in this case is the fact that these scammers have not been met with any consequences. Some people will do something crappy, see what the consequences are to others, and then not do it again. But that latter part requires empathy. Cheri and her goons have destroyed so many lives, but they just don't care. As long as they can enrich themselves, they'll just keep on doing it again and again.
Oh, just to add....the thing I'm more puzzled by are the people who are investing into MTI, and they know (or at least have a reasonably good suspicion) that it is a scam. What they are doing is hoping to make a quick buck whilst they can before it collapses.
The matter of freewill aside, I put these people in the same camp as the scammers. They might not be stealing as much as the scammers, but they are stealing nonetheless.