Why did he have to rape her?

It hasn’t been a problem yet, but now that you mention it...great question. It adds nothing to the film.

Because at that time in the movie he still sees her as a replicant, as less than human, but even then he has doubts as he asks her to say she wants him (or something to that effect)... he is conflicted about her nature and thus how he relates to her...

So it works in the context of the film... It's a portrayal, not an endorsement...

I always thought that people misinterpret this scene as rape when it isn't. Also, in my opinion, many people tend to take this film too literally and miss its allegorical meaning. To me, this movie has a very strong message, which is that it poses the question: what is it that makes us human? And at the end it offers the answer: what makes us human is our ability to feel empathy and love.

To me, the replicants in this story serve as an allegory for people who are emotionless and robot-like, because they are deprived of love. Therefore, Rachel is an allegory for a woman who has never been taught how to love because she missed this experience during her childhood. (It is implied that Rachel didn't even have a childhood, she only has the memories of another person's childhood implanted in her brain). But although Rachel appears cold and emotionless on the outside, the film slowly reveales hints that she has a repressed longing for love.

The reason why Deckard is being violent in this scene is not because he wants to rape her, but because he is trying to awaken her. Rachel visits him in his house and he tells her the truth about her false memories. The moment she becomes upset and cries in front of him is the first time that we see her expressing real, human emotions. Later, she plays the piano and lets her hair down in a symbolic gesture of releasing her erotic side, and wanting to capture Deckard's attention. But when Deckard tries to kiss her, she suddenly tries to leave the apartment. What causes her sudden wish to leave is not repulsion towards Deckard but fear: she could be overwhelmed with emotions, or scared to face her feelings. Then, Deckard violently shuts the door and forces her to face her fears. Deckard has already sensed that Rachel is able to feel love, and practically teaches her how to love. At some point he even dictates her to say: "I want you", as if she doesn't know how to say it.

I always thought that this is one of the most romantic scenes in film history, and I am quite surprised to see that many people have a different opinion about it. Honestly, I don't think it was meant to be seen as rape, or to portray Deckard as sinister.

Harveison Ford

She told him to kiss her after he told her to tell him to do so. What the heck else is a guy supposed to do?

It is not a rape scene.

It is consensual, but Rachael is self conscious because she doesn't know if her feelings are hers or Tyrell's niece's.

The screenplay is plain about that.

The only people who see this as rape are people who have let the deranged, extreme left deaden their libidos.