Skallagrim
Banned
Yeah, this is late, but to me Smith comes off as somebody akin to this cold, compassionless serial killer. His first real scene is him ordering a resistance leader beaten to death not to find any information, but because they already have all the information and they need to find a way to hide it to the surviving resistance members. The scene where he asks the plant if he was authorised to look at the cargo he was carrying just had this really menacing vibe to it, like "I'll smash your skull in with a lead pipe if you do anything against orders, no matter how innocuous". I'm not saying he's the one who would just kill for the hell of it, but if he received orders from high command to strangle his wife and children to death with his own two hands, I would bet all my money that he would, and he wouldn't even have a hint of remorse while doing it.
I think you're completely misinterpreting the character. Smith is not at all a serial killer type. It's much worse. He's a fairly normal fellow, who under OTL circumstances would be a regular world war II verteran and a loving (though rather stern) family man. But in this ATL reality? He becomes something else entirely. Assuming that he is inherently this monster completely misses the point, which is that he represents the monstrous potential in all of us. Under the 'right' circumstances, people who would be basically decent in OTL will instead give in to their darkest impulses-- because it benefits them, because it keeps their family safe and affluent... because it's just so god-damn easy.
Smith is (metaphorically) the embodiment of the idea "if Hitler had won, we'd all be speaking German". Being a Nazi would just be normal, being anything else would be a deviation. One that may well get you killed, or at least destroys all possibility of social advancement, job promotion etc. -- Whereas being a competent military man (a traith the Nazis value), of pure Aryan stock, gives you the exact right position to advance under the "New Order". Just as long as you're willing to shut down your conscience and get started on gassing all blacks, jews, homosexuals etc. etc.
The point being made is that the vast majority of humans would look the other way, just as the vast majority of Germans (not Nazis at all) looked the other way. And men like Smith -- though by no means destined to be evil psychopaths, but career military men, who've seen extensive combat and are already desinsitsed to brutal slaughter -- well, it's almost inevatible that a good number of them become Nazi butchers in a world where Hitler conquers the world. And in OTL, he'd just be your polite neighbour John, who hosts the annual barbeque and takes the lads fishing on the weekend. He'd likely be horrified by the Nazi version of himself, because -- like all of us living in a comfortable, 'normal' world -- he'll have convinced himself that he'd never do such things. But he would. And so would most other people.