#2: Because everyone was afraid that he'd kill them once he became aware of their faults.
Wow, they really thought so little of the guy? He never showed any aggression to the people in the village. Why's was he getting the Gaara treatment?
Murderous Daisuke was essentially a duelist. If he came across someone who attacked with the intent to kill, he'd kill them. Both participants agreed to have a fight to the death. He never went after people who didn't show aggression first.
What made them think he was going to snap and betray everyone? It's a bit extreme, too.
"My teammates and some people in the village acted like assholes to me. Welp, guess I'll kill them all in cold blood."
It's really sad they'd think that of him. Naruto never went on a killing spree and he's dealt with crap all his life.
I mean I can understand him getting super pissed at Hiruzen after he rescued the clan heirs from the monsters. If I did that mission, I'd expect to get a medal of honor and for all the parents to come bow down to me and thank me for saving their precious children. Instead he got punished for not waiting for people who are utterly inferior to him on a time sensitive mission where every second could cost lives.
Yeah, lets wait for backup that's all weaker than me. The Academy is filled with chuunin and they couldn't do a damn thing. If scores of Academy instructors couldn't keep the kids from getting snatched, anyone but an elite jounin wouldn't be any use.
But still not really worth murdering anyone over.
At least, that was my interprutation. Feel free to debate me on this.
Part of what gets people stuck psychologically is that they're only actually capable of experiencing their own point of view. We use words to explain our reasoning, but it's always a battle to get people to understand. If you link your mind to someone else and think about your thoughts and memories, you can experience how another person would perceive these things. It could be a massive breakthrough because you realize that it was your own bad thinking that kept you stuck. That what happened wasn't as big of a deal as you thought or that you're not really a terrible person.
Someone could say those words to you, but when you can truly experience their feelings, it's genuine. It's honest. It's
real. So Anko's exposure to a different perspective on the Orochimaru situation and presumably their future side quest to remove the cursed seals from all his victims and finally kill him for good would help her recover faster than years of therapy.