On the contrary, a lot of journalists have a research bias toward institutional narratives crafted by governing insiders. It does make for a lot less work to draw from official sources since they're the natural convergence point for diverse data sources, but it is subject to elite distortions. They might not consider themselves elite, but those of us in information industries have to work much harder to maintain an unvarnished connection to the vox populi, especially when researching questions the authorities don't want the answers to, or at least don't want to become common knowledge. Developing a rich historiography of a stratified society has always been a problem and has always favoured the elite classes, precisely because of sociological forces that suppress an accurate account of the underclasses. And yes, the CPSU just as the CPC are today do in fact constitute an elite class under a Marxist analysis. I've met far to many ".ml"s who aren't even willing to acknowledge that much. I doubt even the CPSU itself would contest that description, describing it as a necessary, if ultimately temporary intermediate step.

Social sciences are nowhere near as clean as you're implying and the standards of evidence you're applying demonstrate a weak understanding of the subject. Historians have long acknowledged "history" favours the elite because their records and narratives are the ones that tend to get preserved, and you would know that if you were applying honest academic rigour to the problem.