SQP1 I agree, it's not fair for anyone to be shouted down in the crew room just because they hold an opposing opinion. I haven't actually witnessed anything like that but if it's happened, it's wrong!
Regarding the engine overhaul situation there was a very enlightening thread here on;
http://www.pprune.org/forums/showthread.php?t=272153 from Piper19 which gives a very clear engineering insight to the problem in that DHL engineers are further hindered by not being able to find replacement engines and that engine overhauls are time consuming.
I really don't know what the answer is regarding the cockpit fumes saga but Management could certainly help themselves by taking a reality check in acknowledging the problem really does exist. I honestly believe the pilot workforce would then be prepared to work with them to reach a resolution.