When I was in high school in McKinney, Texas, I won a “student of the month” award along with several other students. I went to a public high school, but the award was overseen by the local Rotary Club. The award ceremony was a typical luncheon: baked chicken, big round tables with the boys and girls of the month fidgeting and hoping their parents wouldn't say anything embarrassing.

The only unusual thing about it was that, although no one had stated their religious affiliation, the ceremony opened with a Christian prayer. Better yet, the aim of the prayer was for God to grant George W. Bush a second term of his presidency.

At the time, this was not that surprising. McKinney was, and in some ways still is, a small, conservative southern town—the kind of place where people don't always stop to consider whether everyone else in the room agrees with them.

I hadn't thought much about the Rotary Club event until recently, when I saw McKinney pop up in the news for what would be the first of its two national incidents in as many weeks. On Wednesday, June 3, at least two students at McKinney's Faubion Middle School were sent home after they wore shirts that said, simply, “Gay O.K.” Several others were told to cover over the message. The shirts, reportedly worn to support a seventh-grader who recently came out, bore a message that was deemed “not school-appropriate” by the administration, the students said.

Later, something even more chilling beamed out of my hometown and across the Internet: Police officers responded to a "disturbance" at a pool party in a wealthy part of town. According to some of the teens involved, a squabble broke out when several (white) adults began complaining that many (black and white) teens had arrived at the pool. A white woman slapped a black girl, one witness said, and a larger brawl involving hair-pulling broke out.

When they arrived, police officers told several black boys at the scene to sit on the ground. One white officer, Eric Casebolt, drew a gun on a couple of unarmed black boys. When 15-year-old Dajerria Becton, who is also black, began walking away, Casebolt threw her to the ground and pinned her there, his knees pressed against the small of her back.

Before this month, the last time McKinney made major news was in the fall, when it was named the best place to live in America by Money magazine. It's among the fastest-growing cities in the country, and lately big companies have infused the region with thousands of jobs in fields such as energy and aviation. Starting this year, Money wrote, every high-school freshman in McKinney would be issued a Macbook Air to aid in his or her studies.

"Underlying McKinney’s homey Southern charm is a thoroughly modern city," the Money story gushed.

Southern charm is charming, of course, until it isn't.

As my colleague Yoni Appelbaum described yesterday, the wealthier, whiter part of McKinney, to the west of Highway 75, sits in stark contrast to the older, poorer, and more racially diverse section to the east. Kids who live in west-side developments like Craig Ranch have gated pools and playgrounds nearby, not to mention parents who will drive them to activities. They can easily escape the stifling summer heat or find rides to their after-school jobs.

Kids who live on the east side might be cooped up inside aging houses. Or worse yet, they might be invited to a pool party on the west side, only to be driven away by white neighbors and viciously attacked by the authorities. Perhaps even more depressingly, at least one black woman who witnessed the argument at the pool said most of the black attendees at the pool party were residents of Craig Ranch. If that's true, it suggests that the white Craig Ranchers were engaged in a kind of racism so retrograde that it would make even their great-grandparents shudder.

McKinney is indeed a great place to live for many people. It's safe, has great schools, and even the most determined hooligan would find little opportunity to make trouble. (For a while, the town was completely dry—a quirk that was a constant source of agony for my Russian father but was, in all honesty, likely a net benefit for most parents of teens.)

Despite its rapid expansion, McKinney is still a southern town, with all the attendant politeness and comfort, yes, but also some of the more illiberal elements of southern culture. There were only a handful of mixed-race relationships in my high school, and there were no openly gay students. Before I went away to college, I had only ever met one other Jewish person my age.

I was shocked when I saw the video of Casebolt slamming the swimsuit-clad girl's face into the grass and sitting on her while she cried for her mom. The act itself was horrifying, of course. But I had also never before seen anyone arrested or even hassled by police in McKinney. (There was—and still is—vanishingly little actual crime.) To see my city's familiar scenery, its manicured lawns and cookie-cutter brick houses, as the backdrop to a violent police bust felt like watching a golf tournament on Mars.

The first explanation is simplest: Smartphones didn't exist when I lived in McKinney, so police brutality likely happened and the white residents were blind to it. Police violence against black people has become an epidemic, and it was bound to infect McKinney sooner or later. As Rudolph Bush, a columnist for the Dallas Morning News put it, "Would Casebolt have dared to drag a blond-haired, blue-eyed girl to the ground screaming “ON YOUR FACE!” at a pool in an affluent suburb? If your answer is yes, let me know the next time that happens."

But I also think it's possible that the town wasn't big enough or diverse enough to experience these kinds of collisions 15 years ago. What happened last weekend happened, in part, because the town's rapid growth and sudden wealth has prompted new questions—and provoked new types of ugliness.

Granted, there are some signs that its economic success has slowly nudged McKinney toward some forms of openness. My brother, who is 10 years younger than me and spent his life in McKinney, knows several gay people his age. Last year my alma mater, McKinney High, named its first gay homecoming queen.

But the events of recent weeks suggest that even as McKinney has boomed and prospered, some of the more repressive aspects of small-town thinking persist. Perhaps now that so many have come to McKinney to claim what they feel is theirs—a better job, a bigger house, a more private swimming pool—people feel more entitled than ever to push away anyone unlike themselves. Perhaps some cops believe they have an even bigger mandate to crack down on those who pester the well-heeled. Adults at the pool were reportedly telling the black children to "go back to Section 8" housing, and in the aftermath of the incident, local homeowners defended the police. “I feel absolutely horrible for the police and what’s going on… they were completely outnumbered and they were just doing the right thing when these kids were fleeing and using profanity and threatening security guards,” one anonymous woman told Fox 4 in Dallas.

Outside of its exceptional growth, McKinney is not an exceptional town. Police brutality certainly occurs in many other cities, including northern ones. But the fastest-growing cities in the U.S., by many measures, are almost all in the southern states. Finance-publication slideshows frequently urge young graduates to move to places like Mobile or Nashville.

Many thriving cities have populations that don't share equally in the fruits of their good fortune. San Franciscans still fight over Google buses and soccer fields. In Washington, D.C., wealthy young liberals wring their hands about gentrification even as they eye row-houses for sale. The southern tigers, or whatever you want to call fast-growing cities in red states, must also reconcile their dark histories with their bright futures.

McKinney, more modern than ever, isn't always recognizable as its former, sleepy southern self. (The Money article speaks of its art galleries, boutiques, and, oddly, shoe-repair shops.) But becoming a “thoroughly modern city” doesn't just mean a job at Raytheon and access to craft beer. It implies compromise and integration. It requires an understanding of the fact that, in order for a newly rich town to keep growing, it needs a diverse environment in which every person feels at home. When McKinney tops the rankings as the best place to live, it's worth considering for whom, exactly, that's actually true.