The two girls from the day before were not in Sophia's class! They left as soon as class started! But all of the students of the current image ARE in the class now! So, we're talking about scenes from now on with all together 12 totally different students with changing clothes and different persnickety adjusted poses, plus Sophia and her dforce dress which has to be adjusted/simulated separately for every new pose, plus the background. Try to work with such a huge complex scene a little bit that way and you'll see how funny it is! Especially the saving and loading part!
And yes, a lively city scene with many people and a background life is authentic! So is a classroom with many different students! This all makes the immersion into that scene and story much more intense and AUTHENTIC! Or do you prefer a classroom scene with identical simple black dummies without textures which I've seen in other games? Or city, mall, restaurant etc. scenes with no people in the background as if the story takes place during a zombie apocalypse? For a simple porn game, details and background life isn't important, sure. But I never said it's a simple porn game!