And very much in line with American military tradition. Common carrier transport has been used to send the fallen home going back to the Civil War. Railroads did that through Korea, then airlines took over beginning with Vietnam. It is not practical nor economical to use military aircraft and personnel for this task when commercial carriers are perfectly capable of handling it effectively and with dignity.
+1. I was a Casualty Officer at Ft Lewis during the Vietnam war and handled hundreds if not thousands of transfers mostly through SEA. I personally only directly handled a few transfers and was more involved in the selection and training of escorts, the scheduling of transfers, and coordination with the family. Yes we did check with the Air Force/Air National Guard and would use one of their flights if available but it seldom worked out. There weren't then nor are there now enough airlift assets available and even less when you consider most assets are focused on supporting theaters of operations outside of the US.