I have been concerned about the direction the industry is heading with regards to safety for some time now & what I am reading here just heightens my concern.
The MEL does not decide if the flight goes or not - that is the sole responsibility of the Captain. The MEL is provided to assist with that decision due to the compexity of modern aircraft. Sure, if the problem is an airworthiness issue & cannot be MEL'ed, then the decision has been effectively made. However, just because a unservicable item can be MEL'ed, doesn't mean that the aircraft is safe to fly in the conditions that exist at any particular point in time. The Captain needs to weigh everything up & decide if it is safe to fly - for every sector.
Some MEL's are very grey as well. Our TCAS MEL states the following -
Installed: 1; Required: 0. It then goes on to say "May be inoperative provided: a) system is deactivated and secured; b) enroute or approach procedures do not require it's use; c) it is not reasonably practical for repairs or replacement to be made"
Just what "enroute or approach procedures do not require it's use" means exactly, is open to interpretation. And I would put it to you that the Captain is the one who gets to do the interpretation.
It would seem that management behaviour has forced most, if not all, pilots these days into a position of second guessing their decisions & endevouring to have a covering clause in the manual for their actions. This is leading to a deterioration in airmanship & sound decision making skills in the cockpits of today. And that trend will only end in more accidents as we constantly erode the safety buffer that has been hard won over the previous decades with blood & tears.