Lin's story definitely is NOT all about making her the perfect slave slut. You may not have given her story enough attention. Quite a lot of it involves treating her like an equal, and the structure, economy, and politics of elvish slavery. The biggest overarching theme of Lin's story is, in fact, liberation. What you were doing in the dungeon with Cornwall (a situation you begrudgingly agree to), was try to prove to him that loving an elf and treating them like an equal is the way to go. And if you win, you do exactly that. What you were expecting is what her story is about, please continue playing.
Cornwall, the man you met in the city and who introduced you to how people abuse their slaves is meant to be one of the biggest antagonists in the game. Slight spoiler, but you steal his elves and have the option to give them as much freedom as this society allows while still fighting for elvish liberation alongside Lin.
I get all that, but still it pains me to go through it all. I feel very protective over Lin (ok i am starting to sound like a psycho but i got really invested in this game :P) and all of that arc made me actualy angry.
I get what You wrere doing and You did a great job, the story is great but it still something that made my Blood Boil (in a wrong way).
Again, do not get me wrong, i love the game but i do have my complaints that is all.
I understand, I don't expect everyone to love every event. But it's something she wants to do as well, and of course she isn't in danger during this event. I believe the reader should understand what the world they're changing, why they're changing it, and have motivation to change that world. Changing the world isn't all flowers and sunshine after all.
They're meant to be antagonists, and they're meant to evoke an emotional response out of you, otherwise they wouldn't be good characters.
Honestly my emotional response in that event was because of my lack of ability to protect Lin but i get what You mean and belive me i think it is not written badly or anything. I just wish for a way to avoid not being able to protect her.
Still, this is Your game, I am in no way trying to impose on that. You do Your thing.