Even in the "official" (i.e. in Scene-Relevant Magazines) scene in Germany they're regarded as fascist aligned, just because of their military theme. Yeah, idk man, idk...
The militaristic themes and what I feel is a glorification of war makes me uncomfortable. The use of historical glory from war is so common among fascists and nationalist. And no that doesn't mean that anyone who likes them are, my son for instance like them. But my own personal choice is not to listen to them even though I think that they play good music.
It's the same with Rammstein though (before the Scandal about Lindemann I mean) being regarded as catering to Nazis, because they sang crass texts in, well, German. Completely casting aside the subtle criticism of toxic masculine themes and fascist ideology. Even "Deutschland" was critisized as fascist, when it featured a black Germania and was an in your face criticism of Germany's constant identity crisis and the result being fascism and the holocaust. It's totally missing the point.
And Sabaton isn't taking a side when singing about war events, they sing about the super human feats, but sometimes also about distress, people experienced on the battlefield, about great tacticians and warriors in every age of every nation. That is what Power Metal is about 70% of the time. War. Heck.