I feel like I understand communist theory pretty well at a basic level, and I believe in it, but I just don't see what part of it requires belief in an objective world of matter. I don't believe in matter and I'm still a communist. And it seems that in the 21st century most people believe in materialism but not communism. What part of "people should have access to the stuff they need to live" requires believing that such stuff is real? After all, there are nonmaterial industries and they still need communism. Workers in the music industry are producing something that nearly everyone can agree only exists in our heads. And they're still exploited by capital, despite musical instruments being relatively cheap these days, because capital owns the system of distribution networks and access to consumers that is the means of profitability for music. Spotify isn't material, it's a computer program. It's information. It's a thoughtform. Yet it's still a means of production that ought to be seized for the liberation of the musician worker. What does materialism have to do with any of this?
There's an old saying from chaos magic, and maybe you've heard it in Assassin's Creed as the philosophy of the Assassins too: "nothing is true. everything is permitted."
If I believe in nothing, then I can choose to believe in anything. I find unrealism to be revolutionary.
I think that is a great basis for revolutionizing our ideas, and in many many ways I adhere to that same ethos. I think it needs to be dialectically balanced however with the need to enact real social change on a society wide scale, where things are true given certain assumptions. While the assumptions may be problematic in certain contexts, the outcomes are undeniably real and that is the strength of Marxism. We can deny the symbolic as "truth" but we can't deny the real no matter how we try.
Why not a simple relativist answer to the problem?
"I want to have a revolution because capitalism causes me to perceive myself and others as suffering. I have a subjective distaste for suffering and choose to impose my personal views upon the world by supporting communism. I will use the scientific method to determine which actions of mine reduce perceived suffering, and then I will do those actions."