The issue is that there is no utopia. If you make one, it instantly looks like a cover. "A place of pure light and peace" is hiding something. Even if the DM intended for it to be perfect, the players could certainly see it as a threat. Unless the DM breaks the fourth wall and explicitly tells them it's real, there's no way for the players to know that.

Then, when that place that has tons of resources is fighting some poor faction next door, it looks pretty damning. The same issue as above happens if you portray them as pure evil. There's no way they're actually that evil, and it must be propaganda.

This all happens even more if your players have been trained to spot these things because this is how the real world works.