The sameness is just the carrier wave; the signal is in the details. To people immersed in the subculture, it doesn't look the same at all! You can experience the same phenomenon by listening to an unfamiliar genre of music: it will all sound the same at first, but once you've tuned your ears to the conventions of the genre, you'll start to hear where the variation lives, and the idea that it all sounds the same will come to feel absurd.