Olodan's role in Kagha's story and how the two of them managed to flip grove politics on its head needs to be addressed. Halsin is such a good guy compared to Kagha that it's hard to believe she could turn all of his people around so easily.
The druids arent good though. Charity isnt a tenant of Silvanus, nor is kindness. Their true neutral god doesnt give a shit about others who arent his followers or the forest. Sure, some of his followers might be neutral good, but most are true neutral, some are neutral evil. The neutral and evil ones aren't thrilled to have to deal with a bunch of non-believers sucking up their resources, disrupting their rites, and bringing goblin attacks on them.
It would be interesting to see a tiefling druid in the grove with a hardline stance against the tiefling refugees.
The problem there is that the Druids aren't doing anything to actually solve the fundamental problems either way. Yeah, sure, they can protect themselves, but being a Druid is about encouraging natures balance-and the shadow weave, illithid invasion, and violent, rapacious society of the goblins all disrupt those. Kagha is just being a complete fool and looking at the safety of herself and hers, instead of addressing the actual task which Silvanus grants the druids powers to fix. Hence why Halsin, who isn't a complete idiot, is off doing stuff that actually helps the Druids purpose, in addition to protecting them.
If the ritual were made in such a way that it at least
destroyed the goblins as well, it could be justified as a violent by legitimate solution. Instead of closing off the grove, it causes the entire surrounding area to become violently hostile to everyone, killing all humanoid creatures. Purge the illithid infestation by killing the hosts, purge the goblins, purge them all.
But Kagha isn't a smart, wise, or worthy leader, she's an idiot demagogue whom is pandering to a scared base with a stupid solution that protects them at the expense of actually doing what they are supposed to do. Which, I believe, is part of the intent here.