A guy who girls date who has no intention of a relationship and just uses them as they stupidly waste their youth. Example is derived from women who foolishly toss away their prime years (20s, early 30s) with guys who will never marry them and then when they wake up and want to date real guys, they are too old to marry or have kids.
"She only wanted to go out with good-looking guys, who all turned out to be youth bandits, now she is a Christmas Cake Girl"
"Instead of dating dudes when she was young and hot, she stupidly pissed away her years with mindless pretty boys who turned out to be youth bandits, and now can look forward to a future of being taken for fucking instead of getting married."
"She could have gotten married to a dude, but allowed the youth bandits to steal her formative years."