Actually, it's only up to Hawke to choose to escort the Seraabas, but Petrice or Varnell made the lure so Hawke would be sure to cross paths with the Arvaarad. Had Hawke died in the confrontation, that would have been Petrice's fault.
I was confused what you meant. I thought you meant the trap at the Chantry, if you sided against her.
In any case, to each their own. I hate Qunari myself. It'll take some great writing (and some new revelation) to make me change my mind about them. I wonder if DAI would pull it off.
I don't particularly care about who's backstabbing or "honorable". I do all kinds of scandolous things in games myself. I care about "eternity" as Petrice and Arishok would put it. They both point to the big picture struggle going on here. And someone has to win it, by any means.
I'd prefer honorable actions, but that is merely situational ethics. What's more terrifying is the Qunari ideology in the longrun (or anything like it in the real world). That level of societal control angers me just thinking about it. I'm libertarian to the bone. I don't side with authoritarians, simply because they might have polite methods.