I wouldn't count "blindly following orders" as being unwilling. As Barras explains, the lyrium trick is only possible because templars ingest what they are given without query. And they are in the position they are in because they don't particularly question their leadership, which proudly beats old ladies.
I wouldn't say the templar leadership - which is completely corrupt - is particularly the parallel we go with here. The individual mages are comparable to the individual mages, and I wouldn't say either is more culpable.
Barras also explains that lyrium varieties are already ingested all the time- which undercuts the significance of the red lyrium change. I'd certainly agree it's weak writing, since no lyrium variation had ever been established before, but it does undercut the suspiciousness of the change, especially when (as we have accounts) the leaders demonstrated the 'safety' by consuming it as well.
Instead of the difference between soup and toxic stew, if you didn't already know red lyrium was bad it might as well been the difference between fish and goat. Why wouldn't you trust what your battle-trusted leadership is eating?
I'd also point out the Templar leadership is only 'completely corrupt' if we start our frame of reference after the Breach. We know the Seekers weren't corrupt in the sense that Lambert and his Templars were, since Lambert failed to turn them, and Lambert's only back in control because he and his Templar cabal were mysteriously absent from the Conclave when all the other Templar leaders got killed off.
The Templar Leadership by the time of COTJ isn't the Templar leadership that started or even led the war with the Mages. It's conspirators who positioned themselves to step up after the decapitation strike of the leadership that presumably wasn't on board with them.