I don't understand their reasoning on my "main mistake" at all. I do not see the error.You're right. We are playing different games.
With the next update we'll see which perspective is closer to what L&P is doing.
The major flaw in your argument is the events of Sophia's various storylines bleeding over into all the others. Each one is isolated from one another. Which they have to be, as L&P cannot know which ones players have decided to follow and which they have not.
Sam doesn't have to force Sophia to do anything. Sophia's feelings for Sam will be the deciding factor.
Where I do agree with you is that we can't know how deep Sophia's feelings are for Sam. Because after the hot tub event, except for the brief thought when Sam brought Elli home, there was no further reflection from Sophia about the event. So yes, I also sometimes find that the individual events are too isolated and that the mental reflections of Sophia are missing. L&P has Sophia do a complete reset of her memory between the individual routes so far. This is disturbing to me and makes the flow of the story stagnate.
I would not use the word "force" in this context. What I mean is that after last evening, Sam actually has the right to a positioning of Sophia in relation to her feelings for Sam.