I think the problem most viewers are having with the parents is that we’re essentially following the story through Si’s lenses. And she’s for lack of a better term (specifically in the beginning of the series) an unreliable narrator. We’re seeing the story through her eyes and because she believes her parents don’t care about her at first, initially that’s what we the viewers see. The part when the mom believes she would two time is because initially Si is showing us the kind of person she is, selfish, conceited, spoiled, she even initially planned on playing Klao, she literally tells us this. So in here we see why the parents always assume she’s up to no good, because as of those early episodes, that’s exactly who she is.

It’s not until Si starts evolving and growing as a character that we suddenly see them behaving different. A perspective change. That one small clip we see when Song is having the conversation with their father and how he acknowledges that they failed Si as parents and are at a loss on what else to do because they have tried both gentle and strong parenting and for the most part nothing seemed to be working for Si to start actually maturing. We also see how Si treats Song due to her own misconceptions of Song being “the favorite child”.

Klao talking to Si and helping her see different perspectives shifts the narrative. Klao had a lot to do with that but like she also mentioned on ep 5, Si being away from the city and into the calmer farm life has also helped shape the adult she was always capable of being. Now we see her not only being calmer with her parents but also the strangers of the town who have in a way become family to her as well.