Tourist,
The simple answer to why we do is it that our political masters demand it. They do that because the risk from military aviation is wider than just to the aircraft and those in it. Ministers don't want an accident which involves lots of civilians. Have one, and as a soon as the cause is attributed to airworthiness failure, then the aircraft fleet involved will at least be grounded.
If we were prepared to fly exclusively on isolated ranges with no-one else there and no risk of interaction with civilian air traffic then I expect the airworthiness bar would be a lot lower. The systems airworthiness requirements for RPAS/UAS/'drones' and the limits placed on their operation are an example of this.
In a RAS (and I've been there for several) it's a handful of warships and an RFA in the middle of the 'oggin practising an activity that has been provided for under the Colregs. When it all goes pear shaped, as it has several times, there is no-one involved apart from those doing it. Ships are required to be seaworthy and someone has to sign to say they are. The systems involved in ships are subject to a process similar, but not so stringent, as airworthiness in design, construction and upkeep. It's not so stringent because the risks to all involved are a lot lower. Sometimes this goes wrong too -Upholder anyone?
I agree that it is necessary sometimes to have people die in order to win the battles and the war, or even in peacetime to preserve the lives of the rest of the ship's company. It helps if you have not killed too many of them with faulty equipment beforehand. That's what airworthiness is about.
Albert,
RAS is not that much different from flying a couple of large a/c similar distances apart for flight re-fuelling. That was done regularly and at night too, albeit usually not with the towline above populated areas I expect. The RAF only stopped because the large aircraft with capability as receivers went out of service. I expect it was at least as safe as a RAS though the consequences of failure were probably greater for those involved
N