You are not living in a hunter gatherer tribe where your voice matters, the pay-offs are so low that how your country is run could be about as influenced by your actions as are plate tectonics and you probably couldn't tell the difference.

It's not quite that simple. You shouldn't just ask yourself, "Will my one little voice make things better? Or would exactly the same things happen if I said the opposite, all else being equal?"

If UDT or TDT are at all on the right track, then you should ask, "If everyone who decides according to the same logic by which I decide decides to say this, will it make things better?" The number of people who share your logic may scale with total population, so it might still make sense to speak, even if you are individually an infinitesimal fraction of the total population.