Heck the Divine was receptive to reforming the Circles years before. Before Fiona hijacked the White SPire conclave and Adrien murdered Pharamond and framed Rhys for it.
This was the DIvine who was actively searching fro an alternative to the Rite of Tranquility, remember.
Fiona hijacked it to push a vote, yes, but she did so legally.
Lambert, in his own internal musings wanted her out of the way and a new Divine more willing to let the Seekers do what they will to take her place, and declares martial law even before a vote is actually made and starts killing.
But let's not get bogged down in semantics.
Fiona had fault in the conclave going fubar, but Lambert dealt the first blow of the war and shed first blood, and was acting against the orders and interests of the Divine as well.
The same Divine actively looking for a substitute for tranquility, a rite that had actually been held long-secret by the Seekers as the source of their power and abilities.
Her finding a cure to Tranquility is essentially the very thing that Lambert and every Lord-Seeker before him desperately tried to keep under wraps.
Fiona's biggest faults are, apparently, being hot-headed and jumping into a situation and pulling her fellows alongside with her and provoking a few over-earnest templars, and then having no plan. Lambert's, and the Seekers faults are stacked a wee-bit higher in my opinion.