At the point where she requests Annulment, 'who is at fault' is irrelevant. You don't let a building burn down just because an arsonist started it. You try to put out the fire, then you punish the arsonist.
The fire was already out. The arsonist was Anders, the Chantry already destroyed.
The circle was not involved, and as such, is not the fire that needs to be extinguished.
What Meredith ought to have done is actually take Anders into custody, likely executed, see to the civilians and make sure no debris harmed or killed anyone, lock down the Gallows and search it thoroughly, work with the guard to keep a mob from forming, and be on the look out for Anders sympathizers and/or copycats, and punish them as they appear.
That would be reasonable measures to take in light of the attack with the authority she wields.
Ofc the system is responsible, have their mages been on the Circles it would have not happened.
We know 3 Avvars tribes (JoH, JoH 2.0 and the Stone-Bear), 2 of them almost unleashed Hakkon, so it cannot be considered a exception, their mages are dangerous.
And you cant compare the damage caused by a mudane to a mage, there is nothing compared to a Breach, Blight or possessed dragon.
If you blame their system for Hakkon, does that mean you blame the Circle system for Connor and Redcliff? Or do you blame individuals?
And all mages are dangerous. Just like all guards are dangerous, all nobles involved in the game of politics are dangerous, every soldier and chevalier is also dangerous.
The avaar mages are especially dangerous because they practice a form of magic that Circle's refuse to touch due to religous dogma, but an avaar is no more or less dangerous than a psychologically traumatized Circle mage.
A single mundane, in a single instant, can't match a mage, but mundanes CAN do just as much damage. I mean, it was the Chantry that sundered the veil in Rivain with their exalted march. It's not just magic that weakens the veil between the mortal world and the fade, it can be torn by excessive violence and bloodshed and trauma, like the Denerim alienages's orphanage as a result of Howe's purges, and demons were coming into the world in that orphanage.
Something that wouldn't have happened had it not been for mundane soldiers committing barbarous acts, something that is unfortunately all too common in the lives of elves and the game of politics in Thedas.
Uh in hindsight would you say she was wrong for that?
I mean looking back, The entire circle seems pretty corrupt, maybe that paranoia, that madness, had its roots in reality.
She ended up being right about Orsino, she ended up being right about a great many mages under her authority that were either blood mages or conspiring with them.
And the Grand Cleric, Maker grant her rest was a soft woman, she should have let Meredith annul the circle years before it blew up like that.
But the real question was if she was right because she forced the mages into a position where they had no choice but prove her right because they were desperate, or if they were truly rotten from the start.
I find the Circle system in Kirkwall to be a self-fulfilling prophecy. Meredith saw the dangers of mages and blood magic so put in very harsh conditions on the mages to keep it from happening, but those very conditions made the mages desperate enough to lash out, which resulted in harsh penalties, and eventually many of the mages resort to the tactics she wanted to prevent, and then she uses those mages as evidence to support having those policies in place when most of them probably wouldn't have bothered had they been treated with respect and dignity, as people with emotions.
I don't think Meredith was going out of her way to abuse the mages, but she certainly did nothing to stop the templars under her command who were abusing their authority, and even promoted the extremists who did in fact abuse that authority.
The abuse, lack of accountability of the templars, and extremely rigid and uncompromising conditions the mages had to deal with drove most of them to the very acts she wanted to prevent, when most just wanted to live their lives.
And when the Chantry leadership as a whole says that the Annulment was unjustified, and if Hawke supports the mages, a codex written by another Knight-Commander outright saying Meredith was wrong pretty much speaks volumes on the nature of Meredith's actions.
So in hindsight, I'd say that Meredith's overzealosness created the very problem she wanted to prevent, and most of those mages you mentioned would have been innocent had she not been so harsh, or had punished the templars who actively broke Chantry law and abused their authority over mages.