The problem is solvable in practical terms, because something like this already happened. A group of crackers altered the accounting program of a credit card service in order to create "rounding errors".
Arguably, the amounts were higher than 1 cents and the number of people defrauded was lower than the US population. But this can be extended, as a mind experiment.
In order to solve the problem, you would have to look at who suffered most from the actions. Obviously it is not the credit card holders, who may have lost a couple of bucks each.
The damage was done to two entities:
- First the company that was running the card system, since that such a scandal could damage their reputation badly and even put them out of business.
- Secondly, as you noticed, the Federal Trade Commission intervened, because such a fraud was endangering the general working of the economy (see purposes of the FTC).
Hence the answer to your question is: stealing one cent to every American citizen would hurt the reputation of the agency that did it (voluntarily or unvoluntarily). It would also hurt public confidence (in the problem you are asking about, 325 million people would be affected, so this would be a scandal of vast proportions). This might then slow down the economy, since they would start watching out in case something else is around the corner. The result could in colossal losses to the economy (out of proportion to the 3.25 million dollars stolen).
Hence that would be a seriously immoral thing to do.
This could be abstracted as an issue of political (and/or econonic) philosophy that a civil society -- even if heavily oriented to market economy -- needs to have regulators (with enforcement) to protect its communications and the fairness of trade. In the absence such things, the society might collapse.
Note: As is obvious, this offense is using money as a principal medium and money needs to be protected from fraud. See this remark of Montesquieu : "But, where money is established, [people] are subject to that injustice which proceeds from craft; an injustice that may be exercised a thousand ways. Hence they are forced to have good civil laws, which spring up with the new practices of iniquity." (The Spirit of the Laws, Book XVIII, Chapter XVI)