The correct framing is “since we accept some fraud, the optimal amount of fraud must be non-zero”.
As written, it sounds like society can only function if there is some amount of fraud.
I gave this analogy to a sibling comment of yours. Maybe it will help clarify my point. We accept some adulteration (let’s say it is 2% for conversation sake) in coffee. That’s not the same as “the optimal purity of coffee is 98%”. The optimal purity of coffee is 100% but since we can’t guarantee that some not-coffee stuff has mixed in with coffee, we live with 98%.
But that would be a completely useless thing to say, because we can’t get your Camry to c. There is a whole system of tradeoffs that we all know exists.
Google could easily lower ”bad things” to 0 by shutting down tomorrow. The government could easily eliminate racism by nuking everyone. None of those are interesting or intellectually stimulating discussions.
“Optimal” is different than “perfect”. Everyone else here is talking about it from a system view.
We can't eliminate murders but do we say the optimal amount of murders is non-zero? Instead, the right framing is "we live with some numbers of murders in aggregate because eliminating all murders is impossible". It's not like we need some number of murders for society to survive.
The use of the word optimal implies some murders (or fraud) is necessary for society (or financial transactions).