They are people trained to fight by an experienced soldier. And I would assume that they have at least some experience defending and doing recon of potential threats to their village before they ever went to the dungeon. And no, the first thing the new village chief says is "Welcome to our home, Dungeon Master-sama" (chapter 10, page 7).
She knew the envoy was coming, but it was never shown who would be coming. Just because they told her they would be coming doesn't mean they actually told her how many and the identities of the people coming to the meeting. How would she know the difference between a representative and the dungeon master himself, unless she knew who he was before the meeting?
You are assuming that something like moving away does not happen in real life. We call those people "refugees". And it's not like we're talking about thousands or millions of people fleeing to another area. It's just a village, so a nearby city or town could taking in those people until the military comes in and takes back the village. And rural people are different from city people. Rural people in small towns and villages are much nicer and more welcoming to others than city people. And you have to assume they're under the rule of a local noble or governor that would give them some aid for a short time. Believe it or not, not all bureaucrats and nobles were complete assholes (at least not in real life), and not giving aid to people could spark unrest in their territory, so they have the self interest to do such a thing.
So they knew how to use slings and throw rocks -- that's it. They never used magic or had any sophisticated tactics other than run away and throw things at enemies. And the chain of command is not in shambles at all. They simply killed the man at the top and had the second in command take over. That's hardly something that would leave command in shambles. And if you were literally responsible for the lives and well being of an entire village filled with helpless men, women, and children - would you really gamble on the one in a million chance of the dungeon master being reasonable? Risking the lives of soldiers and guards are one thing, but risking the lives of helpless people that you were put in charge to protect is evil and reckless. Remember, they had no reason to think Nitta would be reasonable when all the stories they have ever heard about dungeon masters and demons are that they are cruel and always inflict suffering to the poor humans they get their hands on. And for all they knew, them being healed could simply be "I spared your lives, so now you owe me by serving me for the rest of your lives". Again, they have never heard any stories of dungeon masters and demons actually being merciful and reasonable, so why would they think it would be different this time?
Btw, the meeting takes place about a week after their raid on the dungeon (chapter 10, page 3). Plenty of time to ask for help, set up an ambush, or evacuate the village.
Who knew that some simple comment that I didn't think too much of would spiral into me typing a bunch of novels for a stupid ero wish fulfillment isekai? lmao
Farmers are selling their daughters as slaves to get by and you assume the local lord gives hand outs and support. Your logic is just plain ignorance at every turn.
would you really gamble on the one in a million chance of the dungeon master being reasonable
That that is what you took from me saying live to fight another day is laughable. Do not pretend I'm saying to submit. I said to play it safe and stall while regrouping and waiting on reinforcements multiple times. He healed and agreed to meet them at a later date, taking advantage of that time given for free is absolutely what I would do, what your advising is to blindly rush in and force a fight to the death right away.
Yes the second in command took control, by overthrowing the old leader, your a fool if you think she has unified control, his old followers who served with him will not just be now listing to her, there will be another faction who is discontent as they lost a means to line their pockets by selling villagers, sure most were purged, but its unlikely all of them were.
Lastly you clearly are very sheltered, that you think being a refugee is a easy or simple life. Even in modern day its brutally difficult as you have to travel to a safe location that can take you, yes they could go to another village, but with how this village is barely getting by on farming to the point they are repeatedly selling their daughters and are still in debt, yeah right another village in the area can shoulder even a single additional family let alone an entire village. Leaving is a last resort, yes they should be ready to, but old farmers who have worked land for generations are notoriously stubborn about refusing to leave their land. They still have cards to play, summoning adventurers, recruiting and finding info, they have no reason to rush to leave now, or to start the final battle.
That you think a sling is simply throwing rocks, and that its a so what is also shows your just lack of knowledge. Ranged weapons like the sling are massive game changers, and speed and damage they do is no joke. That you dismiss them so off hand with no though speaks volumes.
Now I will say you are right ish that she addresses him as dungeon master right off the batt, then says nice to meet you, but it literally means nothing, she was told the dungeon master is coming, so she has to assume the stranger she sees is him. But it doesn't mean she was told the truth, and she knows that. She is simply going along with what she was told with no certainty its true.
Your "tactics" are that your confident in their fighting force against a unknown enemy that you think you know, so you want to use brute force to rush and kill it without any recon or info gathering... were does that sound familiar. Sure as a reader you do know, but you wouldn't as a villager.