I do not "decline to share" in god-belief. I am incapable of sharing in it.
Just like I am incapable of sharing in a belief in Bigfoot, alien abduction, ghosts, the mummy's curse, demons, Klingons, chubacabras, Tinkerbell, bakas, genies who live inside of magic lamps and grant wishes, departed spirits who speak through Ouija boards, psychic healers who pull diseased organs out of people with their bare hands, horse whisperers, or beanstalks with castles and giants at the top. I am not able to believe in things that are blatantly untrue or have no evidence whatsoever to support them.
To say that I "decline to share" in religious belief makes it sound as if there is a real god is sitting there, Yoda-like, clearly visible and large as life, floating in front of me like a turkey on a giant platter. Everyone around me can also see and hear him-- other people, no matter what religion, all describe god the same exact way as I see him.
He is tells me all these marvelous things about the universe, like how to predict earthquakes, and how to develop a vaccine for malaria. I create the vaccine and warn people about upcoming earthquakes. And so on. Millions of lives are saved. I thus have plenty of concrete, convincing evidence that he is the real deal. And after all that, I walk away, shaking my head at this very obvious, visible, incredibly knowledgeable god person, saying, "No thank you, god. I see you and I hear you. I know that you have proven to me that you are the real deal. But because I am arrogant, stubborn and like to sin, I decline to share in believing in you."
That is such a silly scenario that it was actually hard for me to type it out. There is nothing like that wise, useful god that everyone can see and hear clearly. There is no evidence or proof. There are only imaginary stories in old books, wishful thinking, complicated nonsensical arguments, occasional coincidences, plus the human ability to pretend that things are real when they are not.
I am supposed to agree to the existence of a invisible powerful magical being because it says so in a book, and because it would be nice if it was real? I would rather believe in Aladdin's genie or Tinkerbell, then. To my knowledge, neither ever advocated slavery or genocide.