When did I claim that they were willing? You're caught up on this mind control thing like it matters if you were hypothetically allowed to kill them. Willing or unwilling participants, killing the Wardens would be justified if the Inquisitor was so inclined. It's kind of a shame that you can't.
The decision could be pragmatic, political, or just plain spiteful but realistically it could be done and hardly anybody would even bat an eye at it. The Wardens are so damaged at this point and you could destroy their reputation with just their implication in the Divine's death. Guilt and innocence of individuals would be irrelevant at that point.
So again, they got off easy. Time for sleep.
I agree with you on the Inquisitor had full justification to kill any Wardens who resist and fought the Inquisition, a Grey Warden mages who was enslaved, but whether the Inquisitor had justification to purge every Wardens in the fortress, even sane and uncorrupted wardens who surrender or help the Inquisition's soldier fight demons is debatable.
I don't even think the Inquisitor has justification to exile or let the Wardens stay consider how everything happen on Orlais's soil. It's the decision that Orlais's monarchs should take part in this, and should have weight on final judgment not the Inquisition alone IMO.
Yes it can be done, and most people wouldn't even care, but that would meant the Inquisitor is lying to the whole southern Thedas. The truth is irrelevant at this point when people are too upset over the Divine's demise. Yeah, I'd like to see how this decision come back and bite us in the arse in case the next Blight happens in southern Thedas, and there are no Wardens around or not enough Wardens to fight the Darkspawn.
Heh, well we can't have all the Wardens dying at once while the Darkspawn is still around. it's afternoon where I lived.