Honestly just seems like another "gotcha" theory for the sake of it. There are loads of these floating around this fandom and this subreddit. EG has already posted evidence against Nemesis being able to corrupt whatever it wants. But this is not the first time that the "Denerians are working towards a benevolent goal through extreme methods" has come up. And there's just no evidence for it, and plenty of evidence against it. Deidre's comment that they are "saving the world" means nothing. Whether they believe they are doing a good thing, or whether they believe good and evil are meaningless terms, there's not a shred of evidence that Nick's plans are designed to provide some sort of net benefit to the general population of existence, even in his own mind. This is more "What if this bad guy really has a worthy goal underneath the constant horribleness. What a tweest!!!!"