Fifty years after Stonewall, LGBT people who listen to a song, stream a series or read a book have more positive images to draw upon than ever before. But where are our faces in the ads that sell us those things — or, for that matter, pretty much everything? Rarely seen is the same-sex couple sizing up choices at a car dealership, passing around a tube of toothpaste during their morning routine or sharing a smooch as anniversary rings are exchanged. “There’s just a very small group of companies that make an effort to educate themselves and to progress… to...