I don't know, maybe he's a big fan of the Barbie movie (now available on streaming on Amazon Prime videos) and is cosplaying as the Patriarchy. Not even a Ken, but like, the literal personification of the Patriarchy.
Cowboy and cowgirl costumes are fun to wear, but they are just that, costumes. The only acceptable reasons to pretend to be someone you're not on camera is either you get paid for it as your job, or if it is really, really funny.
It's not just the hat. It's posing in a vintage American pickup truck with the American West in the background. It's a persona that has no correlation to this man and has been used for decades as a marketing ploy to sell cigarettes and other garbage so I'm immediately suspect and judgy.
of course, and everyone is free to have some glamour shots taken of them just for funsies, regardless of what they're wearing. What puzzles me though is why vogue is posting this