This would go well under the propaganda tag!

First, get the idea of "objectivity" in history out of your mind. A historian cannot be objective. I'm an American-Jewish person living in the early 21st century with far-left political leanings and about five years of higher education; those things, among many, many other things, color every word that I write, and it's impossible to get away from that. If I were a Spanish mechanic with no vocal political views and no college, that too would color every word that came out of my mouth. In short, you can't write from anywhere but where you are any more than you can step out of your own skin. It's important for historians to realize and account for how their perception warps their work (some already do).

And with that said, on the contrary, distance from an event tends to make it easier to distort an event, if only because it gives historians more time to understand it--and for propagandists to manipulate it. An example I can give from my field is the chronicle accounts of the Peasant's Revolt of 1381. In the summer of that year, according to the most widely circulated chronicle, a mob of peasants angry about taxes rose up from Kent and marched to London. Their leader met with the king, acted rudely, and the indignant mayor of London killed him, dispersing the rebels immediately. That chronicle was written almost a hundred years after the fact, drawing on earlier sources from Latin that were no more sympathetic to the rebels, albeit more detailed, but those details weren't useful for later chroniclers to write down. Another, slightly earlier chronicle paints a very different picture, making the rebel leader out to be a very articulate man and the rebels to be very organized; it also pins the murder of some hundred or so Flemish people on Londoners, NOT the rebels. Why? Well, mostly because that chronicler was a Yorkist propagandist writing for a crown that wanted popular support.

The point of all that is that everyone has an agenda. The chroniclers writing at the time of the revolt desperately wanted to pin the revolt on heresy and demonize those vile brutes. The Yorkists wanted them to be fair and just. The Lancastrian chronicle wanted it to be very clear that they were put down quickly and quietly. We historians in Western academia tend to look at facts that make the peasants look more organized and articulate than the upper class wanted to believe, and we like to think that our using materialism brings us closer to the truth, but the fact of the matter is we're inherently critical of the kind of class strata the middle ages took for granted, and that tinges our writing of it.

All that to say "mind your sources." Your opinion is made up of the source of the information + your personal biases interpreting it. We like to think careful, scientific historiography gets the clearest picture of the facts, but it's not perfect, and outside that, "the facts" are more or less equally plastic. That's a deep rabbit hole historians debate on lately.