Because nobody is immune to propaganda.
I feel like all baby leftists will have a moment where they realize discontent with the current system isn't enough, but have been steeped in the stew long enough they can't actually imagine what a different future would look like(and don't really believe in it).
Like, the spectacle is absolutely fine with showing you what discontent looks like. Propaganda loves the idea of rebellion, it's very marketable. It will never show you what a successful revolution looks like, but it loves it martyr complexes. It's a powerful strain of brainworms.
And once you've caught them you're either bound to shrink back into vague radlibbism, comforted that even if you couldn't do anything, at least no one else could either. Or you start reading theory with doomer-glasses and become a leftcom who's salty no one has pressed the communism button yet and despair nobody will.