I don't think this is a particularly valid viewpoint. For one thing it would destroy half the countries in the world, and most of them aren't highly developed

I don't think this is a particularly valid viewpoint. For one thing it would destroy half the countries in the world, and most of them aren't highly developed nations that can vaguely cope with it. For another, how do you set limits, why is Catalonia special but any random town or city isn't? There's also the point that (probably) irreparably destroying countries based on slim margins and changing whims probably isn't smart. Now that's not to say I wouldn't support a (legal) referendum in Catalonia, but you do need to treat it with some nuance.