For the past 50 years, airline pilots have come from both civilian and military in varying percentage, but always around 50%. Ironically, OP was making a case against military pilots if he was correct in his assertion. The captain on the SWA was likely at least 20 years seniority, so if OP was correct, he/she was military. The fact is that that is an impossible and idiotic assertion that a crew on a major airline made an error because of where they were originally trained. A more logical (and yet not necessarily correct) hypophysis is that the culture and training at the AIRLINE they work for CURRENTLY is an issue.
For US carriers I believe the experience level is higher. For foreign carriers, it is more likely to see someone with little big jet experience. Case in point: A good friend of mine went from flying bush pilot in Alaska to Comair flying commuter turboprops to flying the 787 at a Middle East-based airline in about ten+ years.