I do think that white supremacy, fascism and nazism was really a lot more fringe even only 10 years ago, it wasn't just under-reported.
I believe the person grandparent is referring to's rise to power was one more symptom in what's been happening, and not a cause in any way. Of course, these things tend to enter a sort of feedback loop. If you'll allow me a parallel with the rise of antisemitism in Europe in the early half of the last century: It was not Nazism that emboldened and bolstered antisemitic feelings across Europe. Nazism was a symptom of the established and pretty mainstream antisemitic current in western society at the time. Even the US was not immune to hating on the Jew.
This rise in far-right political strength is most likely associated with a backlash against the (mostly? totally?) left-wing push for inclusivity and rapid social progressivism. In a way, among those that wouldn't identify themselves as far-right but do manifest ideals associated with the far-right of today, I can identify a certain undercurrent of "we're going too far, we're making too many changes, we need to slow down". Of course, things like "cancel culture", Spotify's staff wanting complete creative control over a 'controversial' podcast, etc., as well as the social bubbles we isolate ourselves in on our chosen social media platforms do not help at all with empathy or viewing others' viewpoints, which greatly exacerbates the issue.
That may be true, but far-left movements are certainly gaining speed as well. And I'm talking about real actual 'cease the means of production'-communists. Politics is certainly getting more polarised.
Ceasing it is merely a consequence of botching the seizing (and the understanding of where that means fit in a post-Industrial-Revolution ecosystem of interlocked systems). ;)
And full agreement; this is a language cobbled together by a chunk of land getting conquered and re-conquered so many times that the locals gave up trying to speak the language of the New King and made up their own from their favorite words in the aggressor cultures and the language they spoke amongst themselves.
In a way your comment which, if I read it correctly, implies "surely you don't think that the rise of nationalism could lead to wars" kind of proves my point. It totally could, and I'd add fairly easily. The peace we have is not as solid as it may seem, especially with dwindling resources and the rise of new superpowers in the East.