I don't think my constructed concept is "good" at all. I don't use morality as a tool for evaluating geopolitics, revolutionary politics, and large timescale social movements. It's a form of idealism that obscures reality instead of clarifying it.

Marxism doesn't say anything about "believing in good things". It is a philosophy of understanding the world as fundamentally material, which precludes concepts like objective morality, and using that foundational understanding to do systems analysis on to understand how human society works, understand where it is headed, understand how we can change it.

Actually it's incredibly subjective. Objectivity itself is an incredibly suspect concept and the idea that we should all be striving to reveal the one single objective truth is a feature of failed philosophies and in particular fascist worldviews.

Marxism doesn't claim to be objective, it is a methodology for working with complex interconnected convolutional dynamic systems. Not all Marxists arrive at the same conclusions in theory, and they don't all interpret observations to indicate the same thing. However, as more observations are made and examined, Marxism provides the path to converging closer to a shared and comprehensive understanding, just like any science does, because it's not a series of factual claims but rather a process of developing understanding.