HOLON, Israel — At first it wasn’t clear what the man with the shaggy ponytail was doing at the dinner party. With his bushy beard and crocheted hoodie, he looked like he belonged 20 minutes up the road, in one of Tel Aviv’s hipster pubs – not at this intimate gathering of Jews who had fallen away from ultra-Orthodoxy.

But when he untied his ponytail after scanning the room, it collapsed into long, brown payot – locks of hair that Orthodox Jewish men grow out because the Bible forbids shaving the corners of the head. “This is the magic,” said one of the hosts as she welcomed the latecomer in. “You have seen the magic right now.”

If not quite magical, there was something deeply eerie about the evening’s proceedings. Outside, the town of Holon was sleepy and peaceful: Even as the streets were dotted with secular insignia like stores selling pets and lingerie, they had emptied in deference to Shabbat. Inside this modest apartment, meanwhile, the group of former ultra-Orthodox Jews who had gathered for dinner was none so compliant. Opining on the foibles of organized religion and reflecting bitterly on their past lives, they had convened as much to spite Shabbat as share it.

The number of ultra-Orthodox in Israel, known as Haredim, recently topped 1 million, according to the Israel Democracy Institute. Their population continues to grow, but so does the number of Haredim who leave the fold: In 1997, just 10 people sought help from Hillel, an organization founded in 1991 to aid ex-Haredim as they transitioned into mainstream Israeli life. By 2006 the number had increased substantially to 50, but that doesn’t compare to last year’s 230. And those are only Hillel’s numbers, which don’t account for the majority of yotzim – “those who leave” – whom the organization never encounters.

The reasons for this growth are various and clear. Some Haredi communities have embraced the internet and social media while others use those tools illicitly, but their proliferation has enticed many Haredim to leave their world behind: “Porn sites are not scary,” said Sarah, one of my dinner hosts. “Wikipedia is scary,” and knowledge of what lies beyond communal boundaries can compel many Haredim to seek it. Each departure, moreover, is an act of exponential influence that sets a precedent for others, further normalizing and facilitating the fraught undertaking. Indeed, leaving has never been easier: There are now three Israeli organizations devoted to yotzim, of which Hillel was the first to arrive less than 30 years ago. There are whole communities now waiting to embrace them, whereas not long ago they may have encountered overwhelming disconnect and loneliness. The phenomenon’s expansion is such that, according to Hillel volunteer Beni Naveh, some Haredi leaders are now encouraging families to maintain connections with their yotzim – in hopes that they will feel welcome to return.

Friday night dinners, like the one in Holon, are an effort by some ex-Haredim to reconnect with one another – if not with their roots. I was invited to attend the dinner when I was visiting Israel in March, on condition that I not reveal the names of those present. Some of them, like the man with the ponytail, are only “out” in secret and living dual lives; exposure could mean never seeing their children again.

With their identities concealed, they laid their feelings bare. Sarah made clear that as she sees it, Haredi life is nothing but a theater of the absurd. She wants to write Harry Potter fan fiction as a parable: In her scenario, all magical spells have ceased working but the characters go on reciting them, hoping their powers will one day be restored. These wayward wizards and witches, she said, are like Haredi Jews who live ascetic, rigid, and parochial lives of devotion to an absent God. “I believe Freud would just love watching it,” she added.

As far as the evening’s commentary went, the Harry Potter story was diplomatic. Sparks flew, unfiltered: When a baby boy is circumcised, said Sarah, his family delusionally believes that “a big shiny bitcoin falls” from heaven and they can “level up,” as if playing a game. Though she does not “believe there’s any God who cares what we do,” Sarah resents what strikes her as the highly transactional devotion of the Haredim. “This is what Jesus Christ didn’t like about us,” she added for unlikely emphasis.

Naveh estimates that, like Sarah, about half of Israeli yotzim renounce their faith entirely upon transitioning into secular life. Leaving the Haredi world – what Americans commonly call going “off the derech” (path) – is for this half not a matter of moderation, but of absolution. The meal’s main course was sushi with shrimp – rolled by hand and lovingly arranged in the shape of the Union Jack – prepared by a double-living chef who would later return to the Haredi enclave of Bnei Brak. The shrimp was good, but the choice was clearly polemical: “I had a bacon cheeseburger on Yom Kippur,” said the other host, David, with an audible lilt of pride. Judaism, in his view, is not just outdated, but obsolete. Along with all other religions, he said, it is an institution built on lies, manipulation and self-effacement. He conceded comfort with, even attraction to, casual cultural traditions – but maintained that one cannot be too wary of applying deeper meaning to them. So, though David made a quick kiddush, the evening was not about Shabbat. It was about solidarity among those who had seen through it all and knew better.

“Yotzim culture is really its own thing,” he said. Too often, no matter how secular one becomes, bridging the gap between yotzim and other Israelis proves impossible. Even secular Israelis, said David to affirmative nods, take offense when someone like him identifies as an “atheist” who will not buy into the civic Judaism so central to Israeli identity. And then there is the army – perhaps the fulcrum of Israeli civic Judaism. Serving, said Naveh, is key to fitting into mainstream Israeli life, and to shaking the stigma associated with Haredim who take from the state but give nothing back. Still, not everyone opts in.

Their distinct culture, David added, has really crystallized over the last few years, as the yotzim population has grown and became more organized. Naveh, who is not himself ex-Haredi, agrees with some displeasure. One disadvantage of the community’s recent expansion, he said, is that many yotzim no longer even try to socialize with “the general society. They find it easier,” said Naveh, to be with “people like them who understand them.”

So no one but me batted an eye when, after hours of passionate blaspheming, one guest started gently singing “L’chah Dodi,” a Friday night staple about welcoming Shabbat’s arrival. On the contrary, the rest of the table joined in. In synagogues, “L’chah Dodi” is often festive and upbeat, a celebration of the holy hour. The yotzim, however, sang it in the style of the rabbi and composer Shlomo Carlebach; the melody lilted and yearned towards an almost mournful pall. No one followed the brief liturgical excursion with a hint of snark. For the first time all night, silence prevailed, and something like a proper Shabbat meditation settled over the few remaining shrimp rolls. Proving Naveh right, only I seemed confused.

“We’re emotionally connected,” said David, when I asked him why this prayer was part of his otherwise gleefully trayf Friday night. It’s “nostalgia,” he said – for a way of life that filled him with disdain.

It was after midnight when I left the apartment, and Holon seemed almost frozen. Shabbat had long since been welcomed, but “L’chah Dodi” still rang sweetly, sadly, dissonantly in my ears as I searched for a cab in the silence.