I should probably warn you now, this is, in fact, considered more of a normal game than an H game with H as a secondary component, a side dish if you will. Think of it more like an R rated movie with sex scenes, because R ratings do allow that under certain limitations, in a sea of porn movies.
As for the rest, yeah, there are some scares and yeah player Sensei is the cause of some of the bad things. He is a full blown opportunist and will take any opportunity he can get to be with the girls and get in their pants. The only time he won't is if he is endangering his overall goal of getting them all by taking one or is in danger of losing the girl he is going after at the time by being too pushy.
Let's take Rin for example, she's already extremely unstable and is known not to have feelings for him at this time due to having feelings for another. If player Sensei were to try and get with her immediately instead of waiting until she wasn't on a literal mental cliff edge, she would likely resist, it would likely be forced all the way, and she would likely never be seen again except in a morgue after Futaba finds her.
That said, there are other forces at play beyond anything we as players have the ability to comprehend with what we've been given so far. The Yumi kiss was not him, he was forced to force a kiss on her. That is probably the biggest example in the game so far. Of course, Yumi doesn't know this, so she thinks it was just him and hates him for it.