The original deal wasn't great, but with Fiona being desperate and her back against the wall understandable (imo). It's indentured servitude with the promise of freedom after their dues are paid, or fighting an endless and unwinnable war against religious fanatics. And if they lose? That the templars treat them like human beings is clearly documented in the annullment in which every mage gets a fair trial...
Put aside the pretentious bravado, what else would they accomplish by staying in Redcliffe? Hoping that Ferelden would defend them? Teagan couldn't even deal with the crazies out in the Hinterlands, let alone with the templars in Therinfal if they decide to attack the village.
Maybe red lyrium is not "common knowledge", but I think they could have known. The events in Kirkwall are not exactly a big secret (we have Varrics book for example). And the templars who took it followed an outspoken lunatic by their own accord...for months, even before the red lyrum thing. I can't feel sorry for them.
You give the benefit of the doubt to people that sided with Slaver mages, but damn templars for not following what most thought to be exaggerations from a story telling Dwarf and listening to their commander.
That's the problem and why these discussions go on and on. Bottom line? They're both fuckups, but I find Templars to be the lesser of said **** ups. I admit yes the mages indeed thought they had little choice, but there is always another choice. They chose the bad one. I am a leader of a political/military group that is trying to bring order to a land that is in chaos. I'm not about to put all of that at risk by trusting people with terrible judgement and intellect.
Simple as that. You think that siding with the baddest of the bad is excusable because they thought they had no other choice, which is always the excuse mages give for blood magic, being possessed, whatever, I think that taking a substance you didn't know about when you do all the time from your superiors, and had no real reason to question it is excusable, if naive. The red lyrium at the end of the day is to blame for the templars. That and a demon. Mages have themselves to blame.
Not saying kill them all, but I'm putting them on a short leash. When's the next time they'll do something crazy because they thought they didn't have a choice? I have no idea, and in a war I simply just can't take that chance. After the war is over, maybe it'll be a different story, though I vote for some form of circle always being in place for them, just perhaps with less restrictive rules during peacetime.