As some one who's just interviewed with them for a "Forward Deployed SE, Government" internship position, I did ask what's up with the government in the title and what kind of work I'd do for them. They informed me that the word referred to one of the two products I'll be working on (Gotham over Metropolis) and that Gotham used to be called "Government", something that you can see on Wikipedia as well.
Now I'm not saying Gotham isn't used by gov't, I just wanted to explain what the word actually stood for.
They have a really strong college recruiting organization, which seems to be how they hire most of their people, so glassdoor probably isn't as representative.
For the "FDE" positions, it's much closer to being onsite support/tech/contractor. I assure you Palantir is less shitty to interview for/work for than virtually any "traditional defense contractor", which is their comparison (I've never interviewed at Palantir, but know a lot of people there, including their recruiters, and have worked for the alternatives.)
This is all independent of their "mission". (I support national security but not unlimited monitoring of US citizens; It's annoying that stuff like PRISM deters good people from working for government, lowering our capability to respond, and thus hurting national security...)
I have a friend who does recruitment at Palantir and he told me he has PERSONALLY hired 100 people in the past year. Sounds like quite the conveyor belt of new people coming in. He said it was mostly interns, so I guess they must have a strong college program.
http://www.palantir.com/careers/OpenPositionLanding