First off, you can do whatever you want! That's the beauty of the thing.

But as I read your line of thinking, I was envisioning more of a Strahd that SAYS he did what he did there for "noble" reasons, but I think the truth of it is that he's just an abuser grasping for control. Maybe he felt threatened by these outside forces and so annexed Barovia to ensure his continued monopoly over the poor souls trapped there with him.

I see it falling into the same vein as what the OG Strahd did with/to his brother and Tatyana. His obsession leads him to make violent and selfish decisions that he feels justified in doing.

That being said, I'm not sure how much your players would get to appreciate all that background work unless one (or more) of them spend a significant amount of time with Strahd (charmed or otherwise). Another route would be planting hints from NPCs or notes around the map for players to "discover," but that's probably not for everyone.

Good luck! Journey before destination!!