Is the supply shortage fabricated? There's a ledger in the grove's warehouse that catalogues the usage of food and medical supplies, and it says the druids are almost out of everything. Goodberry and healing spells would make this impossible of course, but it's not uncommon for tabletop game adaptations to selectively disregard or forget about the existence of certain spells.
It's fabricated, they have cows, they have water, they're druids probably they now how to grow crops to feed the cows, they can fish, they can use some animals with wich they comunicate to stealthy catch prey, they can, as last resource, change one of their spells to learn "goodberry".
It's a narrative hole, they just didn't think for a motive for the shortage, the "oh my monsters all around we can not do anything!" doesn't pass a critic analysis of the cove. Had they not put the Cove near a river, hadn't they show bears catching fishes in said river, all the story would had been more coherent, same if thay just said that due to the red allert situation druids had permanently decided to focus only in aggressive or buffing spells with just Nettie and maybe one or two other armed with healing spells.
That being said, I didn't find the druids all that contemptible. Even Kagha, for all she can do, comes off more like a woman suddenly thrust into a role she's unprepared for and whose desperation was taken advantage of by the Shadow Druids, rather than actively malicious. I'd argue Rath is more unlikeable, as for all his whinging about Kagha's leadership, he never extends more than a token effort to oppose it. He does join on the tieflings' side if the tensions escalate to violence, I'll give him that, but it's too little too late at that point.
Nah, I get why they did it, Larian chose to use the usual "insecure one fascinated by evil ideas" excuse to avoid too much complain, but in the end Khaga is just a full fledge xenophobic fella with zero empathy or consideration for anyone outside the druids of the Cove.
@ash elemental: nope, when the battle at the gates happen it's show that the monsters are more powerful than the combatants of the grove, if the battle delays too much the adventurers that accompanied Halsin get all killed (or almost), and those are trained adventurers, a part from Zevlor all the other tieflings are clearly not fighters, even the small group the argue about fighting or not, is obviously weak, and this fits with the fact that they are refugees fleeing to find safety.