Barely over 40 years ago, being "outed" as gay, lesbian, or pretty much anything but a straight-up hetero could cost you your job, your friends, and even your claim to be fully sane. Today, even a Fox News anchor can swan around New York with his boyfriend without raising anyone's eyebrows—as Gawker discovered recently, when it tried to make an issue out of Shepard Smith's apparent sexuality and got only a little remonstrative head-shaking from other media in response.
Those songs, especially when performed by a guy in heavy mascara and leather pants, presented something shocking and new.
One of the catalysts behind this welcome societal sea-change is surely the art and example of the matchless Lou Reed. He may have been the world's first openly out rock star; Mark Joseph Stern has a nice round-up of the anecdotes and evidence of Reed's dalliances with other men. But the point isn't really so much whether he was actually bisexual or pansexual or whatever—it's that everyone thought he was. It was part of his deliberately transgresssive, drug-stabbing, weird-sex-having image. (The weird sex part of his public persona was there from the very beginning, in the Velvet Underground's name. It was taken from a 1960s book about America's underground S&M scene. If that reference wasn't enough of a hint, there's the song "Venus in Furs" on the Velvet's first album, an homage to the erotic novel by the man who gave us the term "masochism.")
Lou (sorry, but I've loved the man for decades, and it just doesn't feel right to call him "Reed") also brought non-hetero characters into the mainstream consciousness through his songs. There's Jackie from "Walk on the Wild Side," a boy hitchhiking across the country who "plucked his eyebrows on the way, shaved his legs and then he was a she." There's whoever he's singing to in "Oh Jim." And c'mon, there's the album art in Transformer.
At the time, those songs, especially when performed by a guy in heavy mascara and leather pants, presented something shocking and new. But "Wild Side" became a hit, and Lou remained a star. He set an example, and a precedent. Along with some of the greatest rock 'n' roll ever recorded, that's a legacy for which we ought to be grateful.