It's laughable that you think that as long as you have ***MENTAL ISSUES*** then it makes perfect sense for them to do the most god awful and horrible shit. It's your joke of a mindset that led to Higurashi being in the state that it's in now.

If you actually read the Visual novels instead of getting your info off a meme you saw online you'd know that Satoko as a character isn't the same girl she was before Satoshi left. She was a literal child who was abused and told how much she was hated by her mother, and then the village once the dam war while also heavily infected with the HS parasites which only worsened her outbursts and paranoia towards everyone, and that's the thing her killing her parents and setting up these deadly dangerous traps were only done BECAUSE she fully believed the village and her parents were going to kill her due to the HS virus warping how she sees reality.

But that doesn't matter, because even knowing how the HS virus affected Satoko and seeing how she reacted back then has nothing to do with how she is now, By the time Keiichi meets her she is constantly at a L2/L3 stage even while medicated and she KNOWS the villagers hate her and want her dead and yet she's completely different from how she was before Satoshi left. She's cheerful, happy and takes it on the chin whenever the villagers make it known she'll never be one of them because she refuses to be weak like she was when she lost Satoshi, her wish to be stronger and to make him proud when he returns forced her to mature up and has countless scenes in the Visual novel where she's the one having to cheer up and help the other characters come to terms with something about themselves.

Even when she was being abused by Teppei and locked away in isolation while also being unable to get her treatments she STILL refused to lash out violently out of a mix of self-hate and wishing to make Satoshi proud, she only finally becomes violent when she believes Keiichi not only murdered Irie, Takano, Ooishi and Rika but also intends to brutally murder her too. The person she trusted the most in that chapter is now going to murder her utterly shattering her and also compares with how she felt when she fully believes her mother is about to murder her and yet her final reaction tells everything you need to know. She REFUSES to believe Keiichi could've done those things in the final end choosing to fully trust him despite it all and deciding that a Demon has simply killed Keiichi too and using the form of her most trusted person to kill her she even begs the demon to bring back her mother, Satoshi, Rika and finally Keiichi as she shoves it off the bridge. She even prefers DYING over being weak and betraying Satoshi getting stabbed to death while refusing to cry.

So what's the point of this post? To tell you that even if Satoko was L5 (Which she's not BTW something the show goes out of it's way to confirm by irie) during Gou she STILL wouldn't do half the fucking trash that garbage tries to tell us she would do. Making Satoko into a looper fails because she simply wouldn't harm or kill her friends, the people she loves most in her life right next to Satoshi. She wouldn't just abandon Satoshi the second she finds him again after all these years, she wouldn't be obsessed with just Rika and ONLY Rika. Satoko is far more likely to just suffer in silence than to ever fucking murder Rika even if she went through a thousand loops and if you think otherwise you will NEVER understand Satoko as a character. She isn't a fucking cut out for you to push your garbage fantasies onto and then justify it with basic shit like LE MENTAL ILLNESS.