The issue here is that the “non authoritarian non state” is communism, and communism for all intents and purposes is just a utopia. It was Marx and Engels vision of a perfect society. It’s nothing more than a fantasy. Utopias don’t exist and never will. When these types of violent revolutions happen and the dictatorship of the proletariat is established, it’s going to remain there indefinitely because communism is an unachievable goal. The theory itself is flawed.

You can stop reading there. Whatever accidentally correct points are made afterwards are just that, accidents. Their(the world poster) initial assumption is wrong. They assume that if communism is not achieved within a few years it was failure, despite Marx and Engels already stating that the transition towards to will take many generations. Communism is also not exactly something to “achieve”. Once the transition into the communist phase of development is completed, that phase too will change and develop. Precisely not a Utopia. Utopia is per definition perfect, ergo unchanging.