I think the fact it’s such an uncomplicated war helps a lot? I mean, the Kaiju are literally trying to wipe out humanity. There’s no ideology or gray area here. It’s fight or die. 

Like, in general, I can’t even conceive of Newt joining a military organization unless it was this clear-cut a war of self-defense. He’ll fight fascists, but he won’t just fight to kill other humans, y’know? He’d fight in a WWII type war but not a Vietname type one, he’d go to jail instead.

And I think on some level Hermann is similar, however, he very much frames himself as a WWII scientist and draws inspiration from figures like Turing. As I’ve said before, I headcanon that he wanted to be an astronaut before the Kaiju arrived, then after he wanted to be a pilot, and then either illness or injury in his leg prevented that so he threw himself into using his other skills to the best of his ability to fight the war. 

I totally agree that Hermann came to define himself as “A PPDC Scientist” in part because he strikes me as someone who is a creature of habit and once he got settled into his routine there, it was hard for him to break that habit. So long as he was contributing to something greater and allowed to pursue his work, he’s content. It was Newt who is always bouncing around and intrigued by new possibilities and opportunities. There’s a line in TOWOID where Hermann notes that with the Precursors taking Newt away he lost all impetus to look for jobs outside the PPDC, because while he was a stabilizing influence for Newt, Newt was the one who prompted Hermann to leave his comfort zone. That’s how I see it at least, the reason why Hermann is still with the PPDC 10 years later with Uprising instead of moving on.

But yeah, Newt sees himself as PPDC because how could he NOT be on the front lines for saving humanity and studying aliens? It’s like joining Star Fleet, in a much darker and more depressing way, but if it ever militarized against humanity he’d be out in a second. Hermann is more into Doing His Duty and being on the front lines because he wants to be at the nexus of the most important fight of his lifetime, his generation’s WWII, but once there indeed the sense of purpose and being part of something greater keeps him there (and perhaps allows him to stagnate a bit, without Newt there).