In her defense, 1) she is hardly alone in her desire; we all feel it to some extent;
Yes, I agree to that, as mentioned previously.
...and 2) she doesn't only feel it when she is the victim of the original offense. If she saw that someone was cheating you somehow, she would want there to be some repercussion visited upon the cheater. In that circumstance, you might welcome those feelings in her;
To an extent, yes, and thus, my dilemma about this issue.
it might make you feel that she recognizes your pain and is on your side. You might think that I'm a bit of a prick because of my relative lack of such feelings.
Agreed. One of my friends felt this way not too long ago. Quick story, but I was with friends, grilling and drinking. Someone grabbed my friend's hat, and threw it in the pool. In trying to avoid much of a confrontation, I said very little about the issue, just mumbled a few terse words of discouragement to the offender, and mostly just watched the situation unfold before me. My friend, the victim, quickly and quietly left, and for several weeks held a grudge against me, one that I see still emerging from time to time, about my lack of caring about him.
He saw me, and continues to see me, as you mentioned, as a "prick because of my relative lack of such feelings".
Oh, and welcome to EVC, AW.