Sleep Rape isnt about force, it's about uncoerced consent. If there is no uncoerced consent then by defination it's rape.

Example: A woman who is blackmailed may give consent, but it is still considered rape. Why?? Because the consent was coerced.

By the same token a woman who is sleeping, especially if she has been drugged or plied with alcohol to the point where she is passed out CANT give uncoerced consent. Her right to choose to say No has been taken away. I dont care how you twist it or try to justify it.. that's rape.