I usually treat 'signaling' as the null hypothesis for human behavior: if the behavior doesn't make sense on its own, I assume it is signaling.

That seems unwarranted. That you don't know why someone is doing something means only that you do not know the reason. I see no reason to think that when people say that organic produce is better than non-organic, that they are not merely saying what they actually think. If there was no-one who actually believed that, how could saying it be a signal?

There can only be such a thing as fake gold because there is such a thing as real gold.