Why, what do you think is their 'simple' solution?
Murdering everyone. This is apparently a non-chaotic evil path you can pick, although I personally have never seen it. The Tieflings will all shout "the druids have gone mad!" while you cut their famillies down and at the end Kagha coldly tells you that you are no longer required, then seals the grove.
How are the other druids okay with this? Are they too "afraid"?
EDIT: Here's proof