Bill Geissele has mentioned he preferred them not being used with his triggers. until recently, you needed to use the pins that came with the Geissele triggers.
As for SEALs, I'll listen all day long when they talk about shooting, team tactics and mindset. What I've found is fighting skill set does not equal firearms knowledge, and it certainly doesn't make one a gun guy. I hope I'm explaining myself right. Cops and soldiers, contrary to what many believe, aren't always the go to guys for firearms advice. But, someone that is a gun guy, whether a desk jockey of face shooter, is who I'll listen to when it comes to knowledge. I won't be asking the desk jockey how to clear a T intersection inside a small structure though....
On my LMT lower, my pins would walk out a bit (all rotate which is fine). I replaced the fire control group and that took care of the hammer pin, but the trigger pin still walked. So, I installed the original KNS pins. It fixed the issue but I eventually traded off the lower for an upper I wanted.
DRM, I'm willing to bet they are not needed on that rifle and they were just installed for the hell of it. That's fine too, just not my cup of tea. Slick rifle either way. For the record, last year an active duty SEAL showed up to a class with a complete DPMS. There's a thread on Lightfighter that talks about it.