There's three gigantic holes in your comparison. The first is that it's been over 20 years since the Second Treaty of Stros M'kai was signed. I've never seen Band of Brothers but I'm guessing that East Company wasn't liberating Eindhoven two decades after the end of World War II. Second is that the Aldmeri Dominion weren't completely crushed and routed like the Nazis were in World War II. There was a ceasefire, there was a peace negotiation and there was a peaceful withdrawal of all forces which would have allowed any analogous sympathizers to leave with the Dominion forces. Third even if something like that would have been going on twenty years later, see above. It would have been going on under the auspices of an official government empowered agency not a resistance. Words have meaning and there is no substantive meaning conveyed in calling anything a resistance that's government run or sanctioned in a nation that's been sovereign and independent for over two decades.
Therefore it is not likely at all that Kematu is referring to situation like that. It is exponentially more possible and reconcilable that Kematu is referring to the resistance against the Aldmeri occupation of territories of Hammerfell because everything in the quest makes sense when taken as the same and otherwise comes off as convoluted, strained, grasping for straws or just nonsensical in referring to sovereign Hammerfell over 20 years later.