However, Marxism is just an abstraction that is related to the underlying epistemological disease of the modern era which is that we use statistics to prove our assumptions regardless of an actual identified mechanism of the phenomenon. We discard the search for the theory because it's hard and we've become accustomed to believing hand-wavy explanations for fields or social phenomenon we are not experts in. Arguably, nobody is an expert here though because there is lots of murky data about these particular topics that is widely dispersed and subject to heavy confirmation bias by researchers.

Instead of looking for the "why" we cargo cult and focus on the other side. IMHO, it's better to understand the "why" whether it's the why of the "ideal curve activist" or the meta-why of the observer of the "ideal curve activist" or the meta-meta-why of me observing your understanding of the issue. However, figuring out the "why" and seeing through statistical "facts" is the only way to really improve our understanding.

In the natural sciences this is easy. We have the scientific method. In the social sciences there is endless opportunity for subtle errors or coming to conclusions that are incorrect occasionally due to error but usually due to sometimes carefully constructed but almost always omission filled perceptions of reality.