I was a little confused reading through this the first time, but the link to the discussion board sheds some light.
It seems that these guys have full-time civilian jobs maintaining Air Force aircraft. These jobs do not provide the same pay and benefits as military personnel but also do not come with all downsides of military service - they are civilian jobs and hence have a union. Sounds familiar so far but, unlike our contractorized servicing, it seems that these jobs also include a reservist commitment of so many days per year plus some deployments (voluntary?). The closest that I can think of in the UK is the met office folks who are civil servants (with a union) at home, but don a uniform when deployed.
The DoD now want these people to wear their reservist uniforms every day, even when they are performing the civilian element of their jobs. It sounds like a cheap trick in order to maintain an illusion of military manning - when the jobs have actually been civilianized.
In fact, it is surprising that our lot didn't think of it first. We could put the Serco gate staff in RAFP uniforms, force the sim instructors to wear flying suits and pretend that the mess staff are actually helpful. Civvies in uniform giving the impression of a military force. The army, of course, would say that the RAF has been playing that trick for years.
