So your standard for morality is people opposing something?
As for the Templars or more the early crusaders, they did "good". They did the work of god. At that time only a christian had rights in their world view. A heathen had NO rights protecting him. There was no such thing as basic human rights that accounted for everyone. They were just the enemy and and their call to arms was rather easy to understand: Kill those that act against god. Taking their wealth was big motivator too, but technically you were not stealing because given they were no christians they had no right to possess that stuff in the first place.
Would I call them evil? No. They were opportunists and professional warriors let lose. From our understanding they did gruesome stuff of which most was just doing their "job" for them. If its not a proper christian, everything goes.
As for DnD it pretty much boils down to how you handle your world.
Is there a true, divine cosmic constant, a law of nature of being good or being evil or is it just an interpretation of domains that was passed down by the gods as their way of seeing things.
I mean, I always thought it was hilarious to imagine drown running around, smirking and giggling and telling each other just how evil they were today. In my opinion they just do "good" in their own way, at last if I want a proper narrative that can be taken serious without an entire race of sunday morning cartoon villains that try to outplay each other just in how evil they were.