Christianity tells us we have free will. God has provided man with a choice whether to believe in Him or not. If God's existence were logically inescapable, there would be no free will to choose whether or not to believe in Him.
God, Christianity, Theology
Given our obsession with self, it is hardly surprising we think it is fine for us to live in a world with malleable moral markers, as long as we get our own way without being bullied by others into accepting their way of doing things. We want others to respect moral boundaries that we want to be free to ignore when it suits.
Psychology, Morality