Unfortunately, many nonbelievers just aren't open about their nonbelief, and there are even those that actively seek to pass as part of the believing majority.
This hesitance to be open to their religious friends, families, and employers is certainly understandable, as atheists aren't exactly the most popular people in America, and many face ill treatment and discrimination because they don't share the dominant faiths. For those who are still very young, or who live in a place where it could be dangerous to publicly identify as an atheist, remaining secretive about one's strongly held convictions seems the only prudent choice.
But remaining silent won't make the problem of prejudice go away. In fact, this silence causes a number of problems for the community to which nonbelievers find themselves members. By having significant numbers in the closet, it makes the demographic look smaller in numbers than it actually is, which makes it harder for the community to fight for equal representation.
Furthermore, failing to openly identify misses the opportunity to put a positive human face on a wrongfully vilified identity. As gay rights activist Harvey Milk noted about another maligned community, "Once they realize that we are indeed their children, that we are indeed everywhere, every myth, every lie, every innuendo will be destroyed once and for all."
And there's another problem with staying in the closet that doesn't have anything to do with political power and grassroots organizing. Outside of any potential overriding safety and livelihood concerns, being silent about one's disbelief may be an unethical act.
According to David Silverman, president of American Atheists, "Hiding your identity means lying to everyone you know, forcing them to love someone fictional out of fear that they might not like the real you. However, given the chance, most family members love the person, not the lie, and everyone benefits from a more honest relationship."
Why is being closeted about one aspect of one's core worldview an untruth? Some nonbelievers will take offense to connecting this decision to ethics, suggesting that their lack of a god belief just isn't important to them, so why advertise it? But that's a weak argument because it's undeniably of vital importance to many people in our society with whom they communicate. Despite the rising numbers of nonbelievers, belief in a god, specifically in the Christian God, is more than a majority idea in America. In fact, 78 percent of Americans believe in a Christian God, and 31 percent believe so strongly that they interpret their Bible as the literal word of God. Lack of belief in a god may not be the dominant issue in your personal life (most humanists understandably have a much more positive agenda than that), but it has to be recognized that it is meaningful to others. If people are to be respected, they deserve to know who we truly are.
Considering the shared aim among nonbelievers to doggedly pursue the truth regarding humanity, the nature of the universe, and everything in it, there is understandably a high ethical standard for humanists and other nontheists to which they hold themselves. There's a reason Americans swear to uphold the truth, the whole truth, and nothing but the truth. And failing to uphold the whole truth (when what's withheld matters) is equal to the other such failings.
While it is always a struggle to reveal something about yourself, such a disclosure seems necessary for those who truly value intellectual honesty. Such clarity helps us to better understand the universe we inhabit, ourselves, and our own biases and fears. And a failure to be fully forthright is a threat to the nontheist movement as a whole.
Closeted nonbelievers once showed tremendous bravery in putting aside the comforting religious stories about existence in favor of a scientific understanding of the universe and our seemingly minor role in it. They must tap into their reservoirs of bravery once more to fight the silence regarding their nonbelief which forces them to jump through intellectual hoops and conceal from those that they care about.