The goal of propaganda is to shut down the minds of its victims. In this respect, statist propaganda has been an almost unbelievable success. It would be scarcely an exaggeration to suggest that 99% of the world population, including those who call themselves "political philosophers" or "social theorists", when confronted with a case for voluntarism, would respond with an endless stream of pro-statist-quo what-ifs, what-woulds, and who-woulds, epitomized by the immortal "without government, who would build the roads" slogan (Bryan Caplan listed some more of them here).
Notice that a voluntarist or a libertarian never responds with his or her own list of such hypotheticals. To ask "what if the government decides to set up a gulag and throw me there", "what would happen if the government decided to kill or maim thousands of civilians in some remote part of the world", or "who would protect me if the government decided to issue a warrantless order to assassinate me" would be ridiculous because these are not hypotheticals at all - this is the reality of statism.
In other words, in the context of analyzing the merits and demerits of statism the Nirvana fallacy is clearly a fallacy, but - for lack of a better term - there is no "dystopia fallacy" corresponding to it. Instead, there are dystopian facts - it would be difficult to think of a worst-case scenario that the state did not already make all too real.
In sum, this is how the situation looks like - while an honest statist would have to acknowledge that the system he supports can be likened to constant teetering on the brink of hell and occassionally falling over it, he will typically cling frantically to the belief that it is the best and only way to organize social affairs and that no logically and economically informed non-coercive alternative should replace it unless its implementation can immediately catapult us straight to heaven.
This is the power of the large-scale, institutional Stockholm Syndrome. And it is because of this power that large-scale preference changes in the direction of non-aggression, non-violence, voluntariness, and free enterprise are so comparatively rare. The only effective tool of countering its influence is to lay bare its ugly nature as often and as clearly as possible, which today, in the age of the Internet, is easier than ever before.