Three problems with your thesis, aside from it being off topic: First, the text does not say that she was "murdered for being raped." It indicates that she was already dead, due to the intense, all night gang rape she had been subjected to (by homosexuals, no less, who preferred to have men, but "settled" for a woman. But that's another subject.)
Second, this account is descriptive (that is, it recounts what actually happened), not prescriptive (that is, it doesn't say that this is what should be done, the way "Thou shalt not kill" does, for instance.). In fact, in context, it is shown NOT to have been the right thing to do.
Finally, this account is from the book of Judges, in a section specifically designed to show the moral chao