The problem with moral absolutism is that established societal moral systems are always flawed. For instance, yes it's a good thing that incest is moraly taboo and therefore illegal in all societies, but then is it a good thing that Homosexuality is also condemed by the majority of societies based on the prevailing ethical codes, and thus illegal in the majority of societies? Not the vast majority mind you, but the majority no less. In other societies rape is not always looked down on as being unethical nore are child brides (who are basicaly sex slaves, and subject to repeated rapes...as are none child brides in some arranged marriages). Slavery was not seen as immoral by the south, who often used the bible to justify it!
I mean honestly, take a look at everything that is considered moral or immoral by the majority in any society including your own and tell me your blood doesn't curdle.
Our law system is NOT based on moral absolutism. Jurors can recomend leniency, though the judge does not have to grant it, and he can grant leniency without them asking or even over the juries objections (hey its his court). The circumstances under which a crime was commited way in on the sentencing phase, and in many can change the very verdict as well. One notable example is justifiable homicide.
Legal systems which require moral absolutism can be found in countries under extremist versions of Shari law, such as Iran http://www.telegraph.co.uk/news/worldnews/middleeast/iran/3179465/Hanged-for-being-a-Christian-in-Iran.html look how that works out, and you should see the rape and murder statistics in these societies.
One cannot demonstrate moral relativism causing an incline in crime (be it violent or petty). The data doesn't back up the constant assertions that it does. Moral absolutism realy has nothing going for it, exept that warm feeling not having to think about things gives people...like religion, and fascism. All nice and warm...