I find it unbelievable that a leader like Halsin could let his grove slip so hard into meme nativist populism, up to the point where even if you help the Tieflings leave and have Halsin discipline Kagha the damage she's seemingly managed to do is irreversible. Is Halsin just full of shit and oblivious to the problems his grove had? How does Olodan facto into this, give that her motivations are just "hail shadow druidry"? Sometimes it feels as though everyone is under the influence of some kind of spell. Not to mention that this makes the shadow druids a totally unrelated evil faction the Absolute's forces can wipe out by accident. Why?
Halsin made some bad calls. I would not say that he is full of shit, but his leadership skills are lacking, or he simply didn't prepare the druids for a scenario were they would be under threat, so when it came down to it the other druids did not know what to do in his absence.
It's the same thing that would happen in any workplace. If the boss/leader leaves without giving proper guidance on how to handle certain situations, things are going to turn into a shit show real quick especially if the second in command is someone as incompetent as Kagha.
Halsin was also probably counting on being back in the Grove and not being absent due to him getting captured.