This discussion seems moot, since it's basically a very ancient discussion of whether "good" is a universal "truth" or relative to each case...
If you're interested in that, please refer to the following terms:
A person who belives that "good" as well as "evil" and what is an example of either is relative is a person who belives in moral relativism, or just plain relativism.
If a person holds, however, that that there are ANY (as in any at all) moral principles that apply regardless social structure, traditions, or taboo, then the person believes in absolutism (moral absolutism).
Considering these terms can be enlightening, and I certainly would not attempt to dissuade anyone from continuing the discussion, but I would still advice people that they should not expect anyone to change their opinions as a result of the discussion, since I doubt a resolution will be reached... After all, philosophers and theologians have struggled with this discussion for a long time, so to me it looks like an undead thread. YMMV.