At the gleaming offices of Minor Ventures, Halsey Minor’s new investment firm in downtown San Francisco, tens of millions of dollars’ worth of art—including expensively lit works by Dennis Hopper, Pop artist Ed ­Ruscha, and contemporary favorite Richard Prince—is displayed alongside gaping, fist-size holes in the plaster walls.

Until recently, several of Damien Hirst’s tableaux of real butterflies suspended in paint hung there. But then the British art star argued with Minor over a work that Minor sold at auction rather than through the artist’s private dealer—apparently a serious breach of art-world etiquette. An angry email exchange ensued. Now it’s war.

Says Minor, “He identically copied one of my paintings for Eli Broad, and it was not part of a series, so as you might imagine, I was not very concerned with what he thought I should do.”

Minor then began dumping the rest of his Hirst collection—at auction.

So it goes with Minor, 43, who isn’t afraid to step on toes, no matter whose feet they happen to be attached to. Though Hirst and his manager declined to comment for this story, there’s no shortage of people eager to offer up a snide (and usually anonymous) remark or two about Minor, who 15 years ago founded the tech-news company CNET and who now runs Minor Ventures.

One former CNET board member calls Minor a “pathological” person who sees everything as “a zero-sum game.” Other acquaintances of Minor’s say that he has burned so many bridges over the years that even those who made a killing off CNET when it went public in 1996 refuse to speak to him now.

I ask Minor why so many people are intent on taking him down a notch. He shrugs. “Warren Buffett is not on Wall Street, and Bill Gates is not in Silicon Valley, and I don’t at all care what’s happening outside Minor Ventures.”

When I first meet Minor, it’s a sunny day at his sprawling estate in Charlottesville, Virginia. The Federal-style mansion is straight from the pages of Town & Country. It has high-ceilinged rooms in which pictures of foxhounds and horses hang above richly upholstered furniture and sprays of pink roses. Along its two-mile driveway are several horse stables.

At the door, I’m greeted by a nanny in a neatly pressed uniform, who holds Minor’s infant daughter. When Minor arrives 15 minutes later, dressed simply in a brown wool sweater, jeans, and expensive loafers, he sinks into a couch and offers a charming smile.

It fades soon enough.

Minor was a star after CNET became the first Web-content company to go public, just four years after its founding in 1992. He was regularly recognized as an entrepreneurial genius in the very magazines that he was intent on putting out of business. The attention was well-deserved. At CNET—which CBS recently purchased for $1.8 billion—Minor started several initiatives that made hundreds of millions of dollars for the company once they were spun off, including the Web portal Snap, the e-commerce site BuyDirect.com, and software firm Vignette. By the time Minor left CNET in early 2000, weeks before the dotcom crash, the company was valued at about $4 billion and his stake at well over $100 million. He was 35.