Which is why both Zathrian and the werewolves are at fault for wanting to kill/inflict irreparable harm to those who didn't have anything to do with their suffering. I really wish there was a way to call out the werewolves for being guilty of exactly the same thing as Zathrian in their attacks on the Dalish, but I can't side with Zathrian thanks to his badly circular reasoning when it comes to his wanting to kill all the werewolves, so I just have to let the werewolves get off scot-free with the ending of the curse. Bah.
If you can forgive the dalish for resenting humans, I'm sure you can forgive the werewolves for resenting the dalish. After all, after being told no, I won't stop the constant burning pain and mind shredding rage I've afflicted you with cause my feelings were hurt, I'm pretty sure anyone would snap and go to the greatests extremes to seek revenge.
I personally hold that revenge is one of the most petty things you can do, for it is cyclical and will create more suffering in its wake to propagate more revenge from those who were hurt in your quest for vengeance. I understand the desire, sometimes the need for vengeance, but I also understand its consequences and the horribleness of it.
Zatharan didn't, and his clan payed the price for it.