Thursday is the National Day of Prayer, the annual spectacle of activists and elected officials, in Washington and around the country, gathering for unabashedly conservative Christian public worship. This year's theme: "Pray for America", because there is a need, organizers say, "for individuals, corporately and individually, to place their faith in the unfailing character of their Creator, who is sovereign over all governments, authorities, and men".

Although the US Congress designated the first Thursday in May as a National Day of Prayer, these organized prayer activities are staged by the National Day of Prayer Task Force, a Christian, rightwing organization. Despite its lofty claims, the NDPTF represents neither all Americans nor all Christians. As just one example of its extreme positions, the group promotes a strain of Christianity that teaches marriage equality is satanic, as pro-LGBT groups have pointed out.

Secularists – not people who hate religion, but people who respect the US constitution and the pluralistic ideals it protects – take issue with the NDPTF's promotion of Christian nation mythology. As has become customary, the American Humanist Association and the Washington Area Secular Humanists are organizing their annual Day of Reason to counter the explicitly "Judeo-Christian" (that is, Christian) nature of the NDPTF's Day of Prayer.

The National Day of Reason has just two members of Congress endorsing its efforts. By contrast, the bipartisan Congressional Prayer Caucus, which is fully supportive of the National Day of Prayer, has 93 members.

That's why Newsweek's cover story this week, its own spectacle of ham-handed religiosity, was obviously timed to dispel a myth so silly that it actually needs no debunking: that "people" think Washington is a godless place, and that Democrats are its godless puppeteers. But, by golly, Newsweek has a news flash for you.

In "The Secret Faith of Washington", the magazine informs us that the nation's capitol is actually crawling with Protestants, who even go to church! And what's more, there's a Muslim in Congress who isn't a part of a secret plot to install a caliphate!

There is a handful of political activists and strategists – including the article's author, Joshua DuBois, the recently departed director of the White House's office of faith-based and neighborhood partnerships – who like to tell us that because there's a widespread misperception that Democrats are anti-religion, they must spend a lot of money and oxygen to tell us just how religious they are.

I don't buy the claim that there's a "myth" out there that Washington, DC, and Democrats in particular, are anti-religion. Sure, conservative pundits and their fans, who never for a moment consider voting Democratic, like to gin up feverish conspiracy theories about anti-Christian liberals or, in President Obama's case, secret Muslims. But those voices don't need to be dignified by a response like this one, which is a cringe-inducing pageant of contrived piety, instead of a defense of disentangling religion and politics.

DuBois opens the Newsweek piece with a recitation of a Pat Robertson screed, which accuses Democrats of being anti-Christian. DuBois contends:

"Robertson gave voice to a perception that's still widely shared across the country: most of America thinks Washington is a pretty godless place."

Anyone who uses Pat Robertson as a compass for "widely shared" perceptions and what "most of America thinks" should be disbarred from offering political advice. Since leaving the White House earlier this year, DuBois has, in fact, founded a company called Values Partnerships. According to DuBois:

"[Values Partnerships] will help public, private and non-profit organizations bring to scale powerful, measurable partnerships with the faith community that solve big challenges, from improving public health to expanding financial literacy to reducing recidivism. We'll also help leaders in the church and faith-based nonprofits navigate the public square around them."

DuBois is not only a columnist for Newsweek and the Daily Beast, but has also struck a deal to compile a book from the devotionals he sent daily to President Obama's BlackBerry. In the Newsweek piece, DuBois cites how he, as a White House employee, delivered these daily devotionals, as one piece of proof that "one of the most faithful people I came to know in Washington was President Obama."

Knowing that he reads a daily devotional, via email, doesn't make me admire the president's moral compass or leadership capabilities any more than if he were reading his daily horoscope. And no, that wasn't a New Atheist-like comparison of the Bible to astrology. Far from it. It's precisely because I think the Bible is a complex, meaningful and often contradictory text that DuBois' comments are problematic. Reducing powerful material to bromides for political gain – by either side of the political aisle – is an insulting and dangerous business.

Millions of Americans pray, millions don't. It shouldn't matter whether elected officials do or don't have a religious life. Prayer offers strong comfort to many people, but it's no substitute for governing; nor is it evidence of better leadership.

And it's certainly not a badge of honor that bolsters political ambitions by further enmeshing religion with government service.

• Editor's note: this article was given a minor amendment at the author's request at 11am on 3 May