I think that this fallacy as it is defined above is not quite coherent. Let me begin my argument with some examples of what appears to be semiotic reasoning that have occurred in more recent times:
Protests and rioting are largely symbolic in nature, especially violent ones involving a small number of people, but that get a large share of attention. It symbolizes anger, it symbolizes that things should change, but violent actions in particular could carry negative or unintended consequences.
The slowing down / reduction of funding towards nuclear energy, because it symbolizes nuclear weapons, radioactive disasters / accidents, and environmental destruction (even though there are strong economic and environmental arguments for using nuclear power especially with technological improvements).
The election of “outsiders” into politics, because it symbolizes the shift of power away from the old elite and the establishment.
More generally, identification or alliance with a culture, group, tribe, or creed that is far different from your own, but opposes the group you consider to be your main enemy (Many examples of this—perhaps the US supporting dictatorships that opposed communism, or in the modern day some parts of the left identifying with Islam, and on the right, public trolling or defense of widely condemned views to oppose political correctness).
It’s not clear to me that the symbolism of an act can be explicitly stated while at the same time, not considering the consequences of a symbolic act.
What does it actually mean for the symbolic nature of an act to be explicitly acknowledged? Is it the belief that an action A represents, but is not evidence for a statement S? Or is it that A represents and is evidence for S? If we explicitly believe the latter, such as believing A causes S to come about or to become more likely, then symbolic acts have consequential intentions. If it is only the former, then doing A might only be useful if we believed someone else thought it was evidence for S.
For example, rioters and protesters believe their actions convey how unhappy they are and have a chance at bringing their message to more and more people. In this case, A is protesting, while S could be “our wants should be met”. A may not be real evidence for S, but it might convince other people that S is true. S could also be “our wants actually being realized.” In this case, the protesters may believe S will be causally influenced by A. They may also believe that other people becoming convinced of S (the protesters are making progress, getting attention and influencing people) may bring about more people to their cause. I think largely the same reasoning could be applied to the other examples.
More generally, let’s say group A is considering taking an action B that has symbolic meaning (it symbolizes the statement C). Why would they consider taking action B? I can see only the following reasons: They want C to be true and believe B is actual evidence for C (it may cause C to become true), or they want others to believe C is true and that their intended observers of the act interpret B as evidence for C.
One of the examples given—that democracy is symbolic of egalitarianism, therefore we should have democracy—would be extremely silly if we actually believed democracy didn’t bring about egalitarianism and that it didn’t convince anyone we were more egalitarian.
So it seems like the fallacy above refers not to the consequences of a symbolic act not being considered, but rather that incorrect inferences are being made about the consequences of the action. If such is the case, then it could be due to other failures in human reasoning, and may not be due to a fallacy all on its own.