Could’ve been a number of considerations....
Runway weight restrictions? non-precision approach at Mojave? runway length? manned fire apparatus/station?
Mojave Max Runway Length: 9502 x 200
Victorville Max Runway Length: 15,050 ft. x 150 ft. precision instrument approach (ILS-Rwy 17/35) and a 9,138 ft. x 150 ft. runway (3/21)
Heck, even Edwards AFB would do in an emergency....
but you might get shot down on approach.