Joey Ryan waited 15 years for this moment. The day when someone wouldn’t automatically associate his folk group the Milk Carton Kids with all those sad images of missing youth splatted across grocery stores in the 1980s. “That is so fucking cool to hear,” he says after learning that I thought the band name was just meant to be reflective of the pastoral, simple life conjured up on the duo’s seven albums, including their latest, Lost Cause Lover Fool , out April 24. The name was in fact swiped from one of the first songs he and partner Kenneth Pattengale wrote, also called “Milk Carton Kid,” in which they symbolically describe the loss of youth as some kind of vanishing act. Still, the connotation has been hard to lift ever since. “We almost changed our name when we signed the deal with our first label, Anti- Records, because that cultural reference was so strong,” Ryan admits. But the label’s president, Andy Kaulkin, pushed back.…