Objective moral standards do not exist. Every being on earth have inherent bias and predispositions and prejudice. That is the way of the world; every species for oneself through self-situating in every case of choice. Free will is also a contested term nowadays, and it seems that synapses in your brain have started transmitting and guiding your body into action before you have actually decided to take action. Rationality; what a strange connection to make in proving God, since rationality is the first thing to forego when believing in a celestial, all knowing, omnipresent being.
The fine tuned universe exists thorugh a series of cosmic events that have spread and made life viable on a few planets, and evolution is the most probable (and indeed the only proven) benefactor of fine tuning. Of course; in christian lore, evolution is a non issue, but then we're back at the rationality point again... If you see a situation or scene in front of you with unknown events having lead up to it, you have a couple of possible scenarios to pick and choose from if you're not very knowledegable about the subject that this situation or scene may concern; a plausible and tangible solution involving physics and basic natural discourses or; a far fetched theory that it was all orchestrated and planned by some supreme being. Many devout christians accuse non-christians or indeed anyone non religious of being close minded, while they themselves are actually openly and conciously opposing and fighting the most logical, rational and tangible solution to a given point.
The best about God is his nature; unable to be proven or disproven, existing perpetually as a figment of some ancient tome's mythology that remains untouchable and immune to ratiolazation or scientific methods with the all-encompassing; "God works in mysterious ways". Way to cover all bases... 
I'll never convert a religious person with my views through reasoning or logical deduction of the prime tenets of faith, but I'll be damned if one of them ever converts me, I feel to intelligent for that to happen!
