The Big Answer is BOTH
there will be no Victim if there are no fraudster , but there will never be a fraudster if there is no victim.
remember that victim is the reason why there are existing fraudster.
so lets not blame one but instead help the victim find a way to not become one.
Your statement regarding something like this can indeed be said to be true because it arises from one of the causes which could be the fraudster's own intentions and could also be from an ordinary person who is negligent in taking care of anything before he is deceived by someone else. So something like this is actually more about the opportunity that is open to the person who will become the victim and the intention of the perpetrator who wants to deceive other people, which causes something like that to happen.
Well, it's the fault of both of them, but the fraudster is the one to blame. He's committing a crime, there is no grey morality about that. You don't question if a murderer committed something bad when it happens.
The parable that you say also makes sense because when you examine in detail the problem that occurred, of course the person at fault is the one who cheated so that any punishment will still be received by the person who cheated, not the victim who was affected by the fraud. So it is clear that if the punishment is defined, only one party can reasonably be blamed, namely a fraudster who has caused other people to suffer losses. Even though he was just taking advantage of the opportunity to vent his own intentions.