1) The Singular Village and the "oldfolk" are the ones that started acting against Hadesman, they enlisted younger people to do a "under the table" type job by lying to them or misleading them that Hadesman was an evil monster.
The larger government / greater power structure of humanity had no clue, which is why the old people had to resort to murdering Fone and hiding their actions.
2) The police women didn't show up to attack Hadesman, they were investigating and would have taken Hadesman's side after seeing the truth with time magic.
This does NOT guarantee the old people would be punished as much as Hademan would like, but it DOES mean Hadesman could have at least TRIED to let human law settle it before he decided to attack the village and harm unrelated people (which as stated by someone else here, Hadesman WAITED to harm LESS innocents because he was thankful to the police women).
This translation might be a bit off, but Hadesman isn't stupid - he's been educated and has lived WITH humans IN human society, he should know that killing a human would make him and his "family" targets for extermination.
This was a family suicide OR he actually intended to kill the old folk even if innocents had to die THEN continue killing every human that came after him and his family for the rest of his life.
Honestly, I thought Hadesman planned to die after getting revenge on the oldfolk which is a bit more noble than "Yeah, I'll just keep killing humans forever until they give up on trying to exterminate us" (If Kredim's translation is correct).
But I do admit that Hadesman being resolved to protect his family after getting revenge (even if it means he'll become the enemy of humanity) and not just kill himself and let them become mindless monsters to be wiped out is pretty responsible of him too...
Well whatever, He decided to answer violence to innocents (Old folk killing Fone) by doing a mass attack that also included the lives of innocents, so while HE DID have the moral highroad, he sank to their level in the end.
Hadesman DID indeed try to avoid killing unrelated humans whenever possible, but a lot of guards he killed were unrelated and just trying to protect the village - not to mention people that died because of the ground collapsing, building damage, power loss, civilians "guilty" of being old enough to be targeted directly by the monsters but not actually involved in the exile of Hadesman or the scheme to kill Fone, etc
I don't blame him and because of our perspective as readers to see ALL of the details in a story, he does invoke more empathy than the old folk BY FAR.
Those spirit hands are the remaining thoughts/mana/perhaps bits of the soul left by the dead.
That's why they wanted to find Fone's remaining spirit to try calming Hadesman.
Edit:
Oh wait, you're talking about the blackhands in the Volume extras? That's just the author being a pervert. He likely isn't allowed to (and it would be a REALLY BAD IDEA for sales) show the girls getting "messed up"(a gentle way of putting it) by human men. Especially before Kikuru has had the chance to do it.
Maybe they might show up in the main story at some point too? We'll see... It IS comedy after-all.