Nietzsche is talking about how the human species, in general, needs a certain amount of irrational belief in order to survive, whether it be religious dogma or political ideologies. Nietzsche's goal was to find an alternative to nihilism.
Yeah, I suppose by simply pointing out the inherent irrationality behind certain philosopher's positions, this still manages to support his own position while also weakening those that think all can have a rational basis.
The Nietzsche quote in question has nothing to do with criticizing other philosopher's positions. He is merely making an observation of human nature, in general.