How many people you know can name every serial killer who ever existed in a row? It’s difficult to hear Eminem openly disavow Relapse. Whether his disparaging words arise on wax during songs like “Not Afraid” and “Cinderella Man,” or during his recent Kamikaze interview with Sway, it’s clear that Em has no love lost for his macabre sixth album. In hindsight, it’s easy to blame …