They send you on what's effectively a suicide mission before letting you so much as speak to their higher ups. They do clearly have means of keeping people out of their bunker.
Also, they have a very insular perspective: You find out that their Paladins were planning to torch The Hub because they got scammed on a trade deal (Although Elder Maxson stopped them). If Rhombus isn't there to inherit the Eldership, they wage a "Steel Plague" on California and start hoarding tech to themselves.
I think it's made extremely explicit that these are a dangerous bunch with xenophobic attitudes, and the capability to wipe out everyone else, albeit one that can be somewhat reined in if certain people(Maxson, Rhombus) are there to tell them not to do anything stupid.