Perhaps we sing from the same book, maybe not the same song.
It should always be that Ops staff refuse the keys if the flight is not legal, and good clubs will do this. Morally so. My problem with your argument (and that of others) is the definition of where your FTO/RTF/Club stops being responsible. This wasn't a training flight after all. I'm touring in France and five days into the trip I float too far and, landing long, run through the fence at the end of the strip. My FTO is responsible because I didn't make the decision to go around? Nah.....
Let's say, for arguments sake, this was a syndicate aircraft not controlled by a 'Duly Authorised' or 'booking out' process? Who is responsible for go/no-go decisions then? The Group Trustee on holiday in sunny Florida? Nope, P1 all the time.
What cannot change is the ultimate decision to proceed into IMC when the aeroplane is not equipped, the crew is not current or competant and overweight or where there is insufficient fuel rests with the P1.