I think we knew from the get go that Kim wasn't going to be our typical gentleman p'ek. Lol. There's different ways to go after revenge. You can go after them physically, emotionally, or financially. In Kim's case, it's emotionally/physically by hurting every woman Tada loves because he lost the only woman he loved in his life, which is his sister. I find his revenge reasonable and not stupid like Kawee, Harit, or Patawee because everyone he's going after is related to Tada. How do you hurt a woman most? Break her heart. How else you'd want Kim to go after them? Kill them directly? Lol. I don't think we want to see that.
With Kawee, he took it out on Rin cause he was mad at her sister. With Harit, he should have done a background check. With Patawee, he shouldn't have involved Som. With Khem from YLC, he shouldn't have involved Rita. But here, Mook is Tada's sister, Pak is Mook's friend, and Dao is Tada's mistress. It triggers a whole chain reaction to hurt Tada because he messes with all the women he loves. Kim can whore around and not care. He lost his morals once he lost his sister and was betrayed by his own fiancé.