I perfectly understand your point, but there is one important thing you're forgetting. While Carolus Rex is an album about Swedish history, this is an exception to their discography. Most of their songs are about praising the military history of countries like Poland, Czechoslovakia, Belgium or Greece, i.e. for the most part, countries that were attacked and invaded by the Nazis. Whenever they do address Nazism, it's in songs like Rise of Evil, Wehrmacht, The Final Solution and Inmate 4859, which specifically look at the dark and destructive aspects of Nazism.
Not forgetting at all, I'm giving reasons for why I think their approach to the whole matter is problematic. They certainly don't want to come off as political, but they've included some elements which they have next to no control over. Symbols, whatever they are, are incredibly powerful and when you use one you know can be controversial you have to have a plan for it not to come back and hurt you. The commercial I posted is an excellent example of a redefinition with the help of context - by having Zlatan, a second generation Bosnian immigrant say those words it effectively neutralizes the nationalistic associations to xenophobia (which are damaging/unwanted aspects of it) and reinvents it for present day use.
Sabaton's plan is their lyrics. Fine, their lyrics are anti-Nazi and anti-war. But until you know that? Their artwork shows nothing anti-anything. I think they could have done a better job at putting the subject in context. Which leads me to the next question - do they really want to do that?
How many wouldn't do a double take on this artwork? You have an eagle, lions, flags, their "S"-logo that looks like a swastika until you actually take a closer look. Sure, it draws attention - Nazi WWII art, uniforms, architecture and symbols were nothing if not striking. But what does it say of the people who uses this to their advantage?
They probably knew
Carolus Rex would be a mild controversy, and they were right - but it also meant an enormous commercial success and a Grammy win. First metal band to sell platinum in Sweden. Not bad. So they continue on their path with their next record -
Heroes. I know the cover above isn't the standard album cover, but it was still used on the release for the digipak and Deluxe edition (as those gold letters tell you). Can you still argue that they are just a metal band who likes to sing about history and overlook the implications they are playing with?
Not really. This is, for me, a pure cynical use of associations to draw attention and for their own commercial gain. They can have their lyrics be about freaking Gandhi, it doesn't change the fact that they have this tension going on. On one side the flirt with these concepts, and on the other the harmless metal band who sing about wars, being anti everything bad and unwanted. If you don't like them, show proof of the former - if you like their music, you can show everyone their lyrics and prove the latter. A done deal, commercial genius of getting something out of everyone - if not a sold record/ticket so at least some controversy and free advertising.
So, to conclude this - I say that what they are doing is problematic. I've tried to explain my reasons for thinking so. I'm not hating on the band, can enjoy some parts of their music, while still not being totally at ease with the tension they create (that I am very critical of).