Yeah, Satoko is literally a blank slate. She's cute and bubbly and there isn't a mean bone in her body, however she's cometely void of any sort of moral compass and has no clue what ethics are. She's an amazing character. Sasuga Burger.
I am actually highly curious how much of her detachedness is a result of most of her formative years being spent in a fugue state where she was unable to register others as individual people (and of course being raised with the standards of killing being a completely normal thing to do, and of any life, including her own, being dispensable).
Even now, she manages to care somewhat about a few of the people she has gotten close to, but otherwise I feel like she still has a bit of a mental disconnect when it comes to recognising a stranger as a person, and not just an animated thing.
And I do feel like, given some of the moments when the author put aside the bubbly veneer for a second, that that is something the author actually took into consideration for this story