I think a lot of western leftism is less focused on building a movement and more on carving out little leftists enclaves where you can LARP like you're living in a post-capitalist society. And the thing is, it's easier to do that under a bourgeois liberal democracy than a AES state. The bourgeois don't care about your zucchini farming commune, have fun fuckers it's not challenge to our power. The Party Chairman who's survived 3 assassination attempts this year alone is maybe within his rights to suspect your utopian commune could become a CIA gun smuggling front and may shut it down.
Anyway that's why I think certain "anti-authoritarian leftists" defend western liberal democracy, internally they're a more welcoming space for social experimentation.