scott Some of this has been touched on, but I had a bit to add.
It's not a Prime Directive issue if the society asks for the captain's involvement. At that point it's
doing her job. First Quinn requested asylum. The protocol was to have a trial. The Q agreed to this and made additional arbitration requests. You said it yourself: "The Q were under no obligation to submit to her arbitration in the first place." They chose to involve her, she didn't just interfere in some other society. This was no different than when Picard was asked to get involved in matters of the Klingon Empire.
Janeway often seemed to me to put her personal pride (I hesitate to use the word 'integrity' since she seemed to vascillate in her principles from time to time) before the welfare of her crew.
Either that or she made the tough decisions.
"The Caretaker": She chose to get stranded in the Delta Quadrant, rather than allow the distruction of an entire species. That's not personal pride, that's avoiding genocide.
Granted, it was a bit merkier on the Prime Directive side than any of the other times, but The Caretaker did ask her to destroy his array. In her mind, as she said, "We're already involved." I'm not saying her interpretation of the Prime Directive was correct, or incorrect for that matter, since we've never seen the entire thing verbatum.
"Prime Factors": She decided not to steal and break the laws of another culture. She simply did her job as Starfleet would have wanted.
"Deathwish": It still wasn't personal pride, it was taking her job seriously. No judge, or acting judge, would be doing the right thing if they let the prosecution bribe them.
"The Q and the Grey": Have my baby and your ship can go home. A woman has a right to her own body (within the limits of not infringing on anyone else's rights, of course). No one could ask her to make that choice. Besides, as others in this thread have already said, Q and his loopholes are not to be trusted. Who knows
when he would have sent them home, amoung other things.
"Scorpion": Janeway is so obsessed with getting her crew home that she's willing to deal with the Borg. Not playing an active role in genocide is the only thing that stops her from following through.
"Night": Janeway second-guesses the "Caretaker" decision, because she cares so much about her crew that she starts to wonder if letting an entire species die wouldn't have been worth it. That's not the act of someone who doesn't care. That's the act of someone who is obsessed with her crew to the point that she'd put almost anything else aside for them.
"Equinox": She chose not to murder innocent beings to get her crew home, that's hardly personal pride either.
Some of her interpretations were debatable. Janeway can be accused of many things; she's human. However, caring more about herself than her crew is definitely not one of them.