I might choose a friend, I might choose a stranger. What I look for is someone willing and able to do the job, and someone who fits in with the atmosphere/culture. Being a friend doesn't put anyone on my short list. It allows me to know their skill set, but it also presents a problem of blinders (which is why I ask for a second opinion or other staffers' experiences of them).
I have had too many instances of seeing someone primarily in one context, and not listening to others saying "yes, they are nice, but are they good for /this/?"
We are not going to see eye to eye on this, Derp. I think that even a good friend can fuck up and fuck up bad, so no matter what there should be expectations/removal procedures and one should never, ever hire someone they'd be reluctant to fire. Friend to friend and staffer to staffer and situation to situation that may mean that it's not a good idea--without it being the case that the friend is a shit. (Or the staffer for that matter).
I know many people I love that I wouldn't hand keys to, and there are relative strangers that I have (the cleaning service people, repair people, a pet sitter). The only person that has ever attacked me or stolen from me, the only person I've ever had to call the cops on, that was someone intimately trusted.
But that's real life, not a game. It's easier to remove people in game. It's (let's hope) less complicated to choose folks that really seem to get what it is that you're seeking for your game. I have a circle of people I enjoy in the hobby, that I'll always make time for, because I adore them. However, I think it improves things to get new blood in there too. Player or staffer.
This isn't a case of me thinking the only way is my way--I would choose something different than you. So? I can see why a friend could be a good choice, I just think one risks the echo chamber if that's made the rule with no external gutchecks. I'm sorry you don't see my point of view, but perhaps it's just a you get it or you don't sort of thing.