It's an oft-repeated expression, yet it holds very little value outside of dictatorial regimes where historiography is stiffled. Still, even under those circumstances you'd call those works propaganda instead of a historical treatise. It's meant to imply that historiography is biased favourably towards those who we consider to have been victorious within a specific context.

There is a very small grain of truth to the fact that cultural and political dominance on a trans-national stage will subjectively impact academics. However, above all else history is still an academic discipline. Historians employ proper tools and methods to engage their own subjectivity through reflexivity.

We can never fully shake our own subjectivity, nor should we strive to. This doesn't mean that an academic paper is an opinion piece void of academic rigour and peer review. Historical treatises aren't synonymous to political treatises or propaganda.