> Basically every history article is heavily biased

This is true, and It's a problem, but it's not a particular problem of Wikipedia; it's pretty much true of history in general.

And not just in the vein of the target language's politics. It's subtle, yet permissive.

For example: if you look at Japanese history[0], many of the atrocities[1] that were committed in the lead up to WW2 are outright omitted, linked to with less frequency that you'd expect, or downplayed. At least, as far as I think they should be included.

I'm not claiming to have a PhD in Japanese history, but I know a small bit about it, and it seems to me (and I can only speak for myself) that there is a distinct lack of 'bad' stuff about Japanese History in the English language Wikipedia.

[0] https://en.wikipedia.org/wiki/Timeline_of_Japanese_history

[1] https://en.wikipedia.org/wiki/Nanjing_Massacre

During the height of the recent Spanish constitutional crisis, the amount of difference (in content and tone) between the English, Spanish, and Catalan versions of the same pages was flabbergasting.

Pretty much every political or corporate sensitive topic has heavy bias. Even biology related topics are subject to external pressure from journalists, politicians and activists. There have been huge fights over how fetus, gender, sex, etc are defined on wikipedia.

And it isn't just wikipedia, it's all of social media and pretty much all of the internet. From silly nonsense like movie reviews to serious matter like war footage, if it has political or financial impact, it is subject to heavy censorship and bias.