What if a country decides that they like a dictatorship? Well, maybe you could argue that they are still deciding that a dictator is what they want. But in general, no matter how a country is run, this does not really give you any ground to interfere with it, whether or not you like how the country is run. If [substantially] more than half of the population asks you to help because they want the country run differently but nobody in power listens, then you might have a basis for action.