I'm in college now and my Ethics professor asked us to find out if the rule of "rape is always wrong" is an absolute. I just want to know someone else's opinion. I already have my position. I just need some other opinions to prove mines correct.
There is no way to "prove" this to be true because it is simply a matter of opinion.
To my way of thinking, you are right and this is an absolute rule that applies in all cases, regardless of whether a certain culture believes that rape is acceptable. The reason for this is that rape harms a person physically and emotionally. I believe that no person has the right to harm another person unless in self-defense. Since rape cannot be considered self-defense, and since rape harms another person, it is an absolute violation of the rights that people have simply by the fact that they are human.