One of my theatre professors in college (just a couple years older than me) wore makeup in the 1970s. Never on campus, only when "off duty". I'd never known an out gay man before (and still imagined myself to be straight).
We became friends, on a first-name basis. The first time I went to his home to ride to a restaurant with him I saw all this makeup and gaudy 1970s-style men's jewelry on his dressing table. Looking very much like a theatre dressing room counter, with a large lit mirror.
He proceeded to put on a foundation, and eyeliner, and a hint of lipstick, and some gold necklaces. Still in his late 20s he really didn't need cosmetics, no aging to conceal. I was kinda shocked, and a little uncomfortable to be seen with him. But I learned that night an important lesson about loyalty to one's friends, which is another story.
And so I always think of him when I encounter gay men wearing makeup. But still don't wear any myself, even though I undoubtedly could use some "repair work", these 40-some years later.