How did Mike Beuttler make history in Formula One?

Beuttler is often described as the first openly gay Formula One driver, although former Autosport editor and friend Ian Phillips has described Beuttler as "semi-closeted", adding "I'm not sure anybody really knew. We all just kind of suspected it. Because people weren't open about being gay in those days and he took this lovely girlfriend to all the races which I suspect was just to distract because people didn't come out as being gay in those days."