"Workplace Violence" Again?

Just as with the Fort Hood shooting, the beheading and stabbing at a food processing plant in Moore, Oklahoma is being treated as "workplace violence", which has some terrorism experts befuddled.  While it's true that the incident occurred at the place where the suspect, Alton Nolen, had been fired, he had disparaged non-Muslims and stated "Sharia Law is coming" on Facebook, where he also posted a picture of a beheading.  The attack occurred just a few days after an ISIS leader called for the killing of "disbelievers".  Nolen is in a hospital recovering from gunshot wounds, and will be charged with first degree murder.