i'm sorry, but your argument just isn't supportable by facts. to say that our present society and its moral and legal frameworks aren't products of thousands of years of history and evolution is ridiculous. its preposterous. you rightly point out important historical transformations that brought change, but you completely miss the fact that those changes didn't just happen in a flash, completely divorced from the societies they came from, driven by just a few people, and they certainly didn't completely eradicate everything that came before them. they were evolutionary stages in social development. history comes in ebbs and flows. there are reactions and counterreactions. i believe that there is an organic wisdom in conservative societies that generally bends those changes towards positive ends. problems occur when societies or states get highjacked by small groups who feel they know better and try to bend things to fit their own narrow ends.
many, even most values, aren't absolute, and of course they can change, but some values ARE absolute, and those that arent better change slowly and incrementally, not quickly, or arbitrarily, or to suit knee-jerk, narrow public opinion.