I'm looking at the situation as being railroaded into an outcome I'd oppose. If this hypothetical situation involved the protagonist being forced into killing the templars and helping the mages to deal with the crisis of the veil tears, I doubt you'd be making the same argument.
Railroading happens Lob. Cheers to killing Red Temps and psycho mages.
Plus your assumption like DKJaiden before you about my liking of the Templars is way off the mark. My Warden's a mage, helped the collective, saved Ferelden's CoM, ended Zathrian's curse with the Dalish as allies and asked for the Magi Boon (other choices were lame), while in DA2 i sent Feynriel to the Dalish then to Tevinter, let Grace's group escape as Kerras raping Alain is awful then sided with Kirkwall's CoM at the end of act 3. I mostly debate pro mages as i'm not an idealist and don't see most of DA's conflicts in black and white.
About me being railroaded into killing templars? I don't care so long as they aren't reduced into caricatures.