Focus groups are not replicas of polling data, and they represent only a snapshot of views. That is a fact pointed out by Tony Sciullo, a Republican-leaning independent who voted for Mr. Trump.

“I surely am not his base,” Mr. Sciullo said, calling himself an “anti-Hillary voter” and adding that Mr. Trump has a strong base that was not factored into the attendees. If any of them “were in this room, they would be vociferously defending him,” Mr. Sciullo said.

“I believe that some of them are actually good people,” he said. “I’m not going to demonize them. They’re missing a lot of the points that most of us feel are not subtle.”

Christina Lees, an independent who leans Republican and voted for Mr. Trump, declared that “everybody knew he was a nut,” but that they hoped for him to achieve good things when they backed him.

It’s “time to become professional,” she said.

Brian Rush, a Republican who said he voted for Mr. Trump out of frustration with the status quo in government, said he had grown weary of Mr. Trump’s “antics.”

“I look to a president to be presidential,” he said, adding that Mr. Trump had started playing aggressively toward his political base almost exclusively.