I have never had any issues with people keeping the fruit of their labor and their wise investments, but unearned income has always seemed to me to be a form of theft.
You know, kinda like slavery. In fact, exactly like slavery.
No, it's you who are stuck & addicted to Marxist dialectical materialism explanations for historical events.
Like you, Marx insisted that only economic explanations and class warfare truly describe historical events.
Marx took the older Hegelian dialectics, which did allow for more spiritual motives (i.e., ideals & religious beliefs), and said, in effect: "no, it's all just economics & class warfare, so follow the money."
For a brief introduction to Marx's dialectics you can start here.