Rape is a crime about power. When the victim "goads" the rapist on, the rapist feels that he/she is getting the power from the act--the very power they committed the act in order to gain. If the rapist is resisted by the victim, it begins to cut into the amount of power and control that the rapist has over his/her "subject."
Given what I've said--that rape is a power crime--it would make sense that a rapist (seeking power) would give up where he/she could not get that power and only follow through in the instances where he/she can. So, when a rapist decides to carry through with the act, he/she makes a logical decision based on what will get him/her the best result, i.e., more power. I fail to see any bit of empathetic feelings in a decision like this.
To experience this sense of power one must 'know' that the victim is powerless. This requires empathy.
This doesn't require empathy! All the rapist needs to concern him/herself with is whether or not there is resistance. When an animal of prey goes after the helpless injured deer before trying to take down the healthy and strong one, do you think that's empathy? The animal (like the rapist) is looking for the path to their goal (food for the animal, power for the rapist) that will offer the least resistance.
If the animal attempts the deer likely to put up the greater amount of resistance and it gets away, the animal doesn't get its meal. If the rapist attempts to rape the individual which is puting up the greatest amount of resistance, he/she doesn't get his/her power (or at least not as much). The only real difference here is that the rapist can't decide which individual will put up the greater amount of resistance until he/she has already begun the act--though this can be true of the animal as well.
Empathy is not a synonym for good or for moral. It is a tool, an ability which can be used to help discern good from bad, moral from immoral.
But then you must show us how "moral" = "doing what is good for others." I believe that "moral" = "doing what we think is best," and how we arrive at that conclusion may be by taking a number of things into consideration, but not just the feelings of others.