Imagine playing a H game, pure, had cleared level 3 (beaten 3 bosses) and complaining the new gym addition is slut only Karryn. Like bruh, why not just play a normal RPG. It just doesn't make sense for her to not be slutty for the gym DLC to happen....
The main feature of Karryn's Prison is Karryn's journey along a path full of corruption all around.
And most importantly, before this DLC, you could go through the whole game with a low level of lewdness.
Some players, of course, corrupt Karryn by the middle, and some even from the start.
But the main thing here is one thing - variability.
That's why players praise this game among all other games, where in-depth path choice is almost never the case.
Certainly, it takes a lot more work on the project from the developers.
But ordinary players, seeing the huge potential that almost no other RPG has, are simply disappointed.
And therefore it is not hard to understand them.