I found this helpful in understanding the mystery of Trump's approval ratings: 

They are country-club Republicans who long voted for business-friendly politicians like Gov. John Kasich, who represented the 12th District in the House and is the national face of never-Trump Republicans.

One Dublin man who is a former Ohio assistant attorney general, and who now owns a manufacturing business, said he wrote in Mr. Kasich’s name in 2016, rather than cast a ballot for Mr. Trump. “But now I’m a big supporter,” he said of the president.

He asked to be identified only by his first name, Sam, because he fears a backlash for his business if he publicly supports the president.

“I feel he’s done a marvelous job,” he said.

He added: “I can’t stand his personality and behavior.”

Other men who back Mr. Trump in Dublin were also unwilling to let their full names be used. They did not want to inflame clients, colleagues or family members.

“Behind closed doors there’s very, very solid support,” for Mr. Trump, said Charles McClenaghan, a lawyer, who is president of the Dublin Republican Club.

“I think that’s exactly why the polls got it wrong in 2016,” he continued. “People felt intimidated, they felt bullied. They’re just not going to talk politics. But when they get in the voting booth, they’re going to look at the wonderful success he’s had.”

and this

The next day at the Golf Club of Dublin, two other players finished their games, a veterinarian and a medical physicist, and sauntered into the Tudor-style clubhouse, where they ordered chicken wings and beers.

The golfing buddies were on opposite sides of the nation’s roiling political gulf, but had managed to remain friends. “Can I try one of these?” the veterinarian said, reaching for the physicist’s plate of Buffalo wings.

Paul Lundahl, the physicist, who works in cancer treatment, said he had long been apolitical, “reluctantly” voting in 2016 for Hillary Clinton while not caring much about the outcome.

“I’ve never really considered myself a Republican or Democrat or whatever,” he said.

But he has grown to detest Mr. Trump.

“I just cannot believe what comes out of that guy’s mouth every time he speaks,” Mr. Lundahl said. “I feel like I’m on the playground as a second-grader.”

The veterinarian, who would only be identified by his first name, Steve, was a fan of Mr. Trump’s.

He praised the Republican tax cut because it put more money in his clients’ pockets, which has meant more of them come to his clinic for heartworm and flea treatments for their pets.

“That helps me,” the veterinarian said. “So I don’t really care what the president says. He’s a crude guy. It’s embarrassing. But what he’s done is what he said he was going to do.”

He credited Mr. Trump for getting Justice Kavanaugh confirmed and for meeting with the North Korean dictator Kim Jong-un. “How many people over the past 50 years between Obama and Clinton and Bush failed?” the veterinarian said. “Who made the deals? Trump did.”

Mr. Lundahl has become so numb to the president’s trampling of political norms, he said, that he recently decided not to talk anymore about Mr. Trump. “It’s so exhausting,” he said.