Cultural differences. He's said to be a "sunbae", making him older. So sitting in front, running errands is "normal" because as a younger person you can't do much about it if the older person turns out to be a bully (or a kkondae, as they call them).
He likely didn't expect that anything would happen, and as I said, wasn't in a position to refuse neither.
His dad also isn't a random professor but a famous researcher. It was also explicitely shown what happens when people know about his connections, as they keep talking behind his back and giving him a hard time. If rumors got out of hand it would also discredit both his hard work and his father's reputation. So no, it's not like "no one would care" as it was explicitely shown that people did.
Also why are we blaming the victim I'm so confused lmao
I'm not blaming the victim, I'm blaming the author for making him stupid even though he's supposed to be smart. No one would choose to get raped over having people talk behind their back.
Even if the story treats rape as a serious topic it does not take it seriously enough, and that's the problem. It's in so many bls and authors just brush past it...

Let me get this right.
1) He asks you to sit in front of him and you do it? That's just a weird request and you don't even know him.
2) He's being a creep and instead of avoiding him you go to an enclosed space alone with him to "talk". Mf what could be so important...
3) After he assaults you, you go again to not get exposed as, checks notes, a human being. No one, literally no one cares who your dad is. Its one professor out of all the classes you got, you can literally stop attending it if it's such an issue...
Gotta be one of the dumbest main characters I've ever seen. Idk maybe it's cultural differences but I really don't get his way of thinking. And it's a copy paste personality for so many stories.