“We’re flat-earthers,” Ronco said, describing the view of people like himself that has taken hold. “With total disrespect for the system and humanity itself.”

But Ronco says leaders are overlooking how their moves are cleaving society into two groups, one accepted and one not. As Italy, over months, built up its Green Pass rules — first for indoor dining, then for workplaces, then for public transit and much more — Ronco turned his Facebook page into a mix of Torah passages, cello movements and fiery claims about government overreach. He re-shared the testimony of various vaccine skeptics and in the process lost roughly 1,500 of his 5,000 followers, only to find new friend requests pouring in — presumably from people who were more like-minded.

Most of that churn didn’t matter to him. But one consequence struck a painful chord. He’d been close friends with an expert Italian stringmaker — “we were like brothers,” Ronco said. When Ronco visited the string factory several months ago, his friend had enforced masking and distancing and temperature checks. But the visit, Ronco felt, had been warm.

Then, a few days ago, the stringmaker unfriended Ronco on social media.