So what? I should just leave well enough alone while they continue to murder, steal, and rape when I am in a position to stop them? I could never do that.
You put the measures into place that the ideology, the notion, the idea fades from memory and it actually achieves something.
Merely killing them? Their Order will be replaced, rebuilt and in action again within a decade. (Likely with the same perks)
I wouldn't kill you! 
Unless you killed innocents and had your way with commoners.
Then I would kill you.
...You wouldn't be the first try, Would prove interesting if nothing else.
That said what if i had my way with commoners and then paid them? Or you know ._. gave them employment or other motivations to take to my Bed, you know like Nobles oft times do even in dragon age, Its all exchanges, That said Peasants occasionally revolt and then they need to be put to the sword.
...Then you need to import new peasants.