I don't know - perhaps because it was damn catchy, and people just weren't listening to the words. Perhaps the melody and the vocal, both of which were very strong. Maybe, as Elton John would sing a decade or so later, people just like sad songs.
Whatever the reason, Gilbert O'Sullivan's "Alone Again (Naturally)" dominated the airwaves during the summer of 1972, and became the unofficial theme song of our first family trip to Disneyland. I think it's a great song, and one that has held up well. I'm not sure what happened to ol' Gilbert, but he was on quite a roll for a few years.
"Alone Again (Naturally)," Gilbert O'Sullivan, from the summer of 1972.