That's why the scene is problematic in the book, too. He's forcing himself on her, she's saying no and trying to physically stop him. There's no indication he's going to stop whatever she says or does. She makes a sudden switch to consent. Had that been filmed it could easily be seen as sending a "no means yes, just keep going until you get a yes" message.
I think there's a difference between "no I don't want to have sex here" and "no I don't want to have sex with you at all." If directed well, I don't think it would have been that problematic.
The problem with the scene as it played out on TV was that the circumstances were different. They were more at odds with each other than in the book, so it's hard to say what her feelings were toward him sexually. It appeared as if she didn't want him that way anymore. And the scene cuts off prematurely, so we also don't get to see the aftermath. So the way it is, it's kinda hard to not see it as rape without further elaboration. It was poorly directed if that wasn't the intent.