crazyhazy, while you make some points in your op that are indisputable empirically, i think they're are some flaws in logic.
while there are many people who claim to "know" what God wants us to do based on reading what are some very old texts, indeed, this does not mean that those books were necessarily written for that purpose. Nor is it of any value (for argument's sake) that these religious texts are very old.
In my opinion, the purpose of the religious text is to provide a space for spiritual meditation or the contemplative pose. By and large, the world's religions preach similar primary messages: Love each other, take care of each other, and be happy. Many eastern religions focus this through the lens of divesting yourself of desire which, in western terms, means getting away from materialism. If one reads these texts--the vedas, the upanishads, the mahabarata, the bhagvad-gita, the bible (in all its incarnations), the tora and talmud, the koran, the writings of great religious leaders and philosophers--it can offer great instruction on how to approach, how to formulate and maintain, an existence in which love, peace, justice, and happiness are maximal.
I agree that many institutionalizations of these messages have fallen to the corruption which always becomes possible when power structures are invested in those institutions. what this means, i think, in short response to your op, is that the problem is not with the religion itself, but with the churches, mosques, temples, etc.
I think there is an instructive Buddhist vis-a-vis Hindu principle that you will find enlightening and agreeable: Do not believe anything that does not make sense to you. or, contrariwise, believe only that which makes sense to you.
NOW, the whole bit of searching for proof in all this, well, you will never find that. there is no proof. that is why these become matters of faith and debate. We can sit on and argue endlessly about the merits of rationale, emotion, spirituality; we can go back and forth on moral conundra forever; we can approach philosophical questions from diverse vantage points and still resolve nothing. Thats, in my suspicion, part of the fun of being a human being. God, or whatever you want to call the primordial force of the universe, had a pretty good sense of humor when he started the evolution of man on earth: now there's a whole big faction of our species that does nothing but sit around and argue about what our purpose in existence is when it has never changed: be happy.
my two cents
be easy
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above I say "what God wants us to do"... I think, upon reflecting, God doesn't "want" us to do anything, as God doesn't want. So, it is better to formulate the discussion through the language of our purpose. I believe that was a clear point covered above: our purpose is to be happy. The hard part is figuring out the "how" of that "being happy," because it is subjective--specialized, if you'd like to euphemize--