Hi Bealzebub,
I think we all agree that no one wants to see a degradation in safety. The issue that I've got is that none of the aviation colour vision tests actually test whether we can safely perform our duties as pilots. All the tests throughout the world are basically colour naming tests which are designed to be difficult for colour defectives to pass. Most of the tests are conducted in laboratories and are not reflective of the environments that pilots operate in.
Visual perception is a hugely complex area and a decision on whether a pilot can operate safely needs to be based on evidence. Aviation authorities throughout the world assume that because we can't name a colour that makes us unsafe. These decisions are typically made by beaurocrats who have normal colour vision and have no idea what us colour defectives see or how we've learnt to adapt throughout our entire lives.
I fly for an airline in Australia and regularly fly into busy international airports at night and often with weather conditions such as those you describe. I do operate EFIS equipped aircraft. I do fly approaches using PAPI. I am regularly assessed in both the simulator and on line checks in the aircraft itself and have always passed without any issues whatsoever (and have done so over my last 15 years of flying experience). However, when it comes to colour vision tests, I fail them miserably!
There are many other examples of professional pilots just like me in Australia. Therefore the link between an individual's ability to name colours and being able to fly complex aircraft in complex environments is tenuous at best. The fact that I can have a rewarding airline career here in Australia, yet if I was to go to Europe or even across the Tasman to New Zealand and would be restricted from even flying a C172 at night surely highlights that there is a major problem with the standards and the assumptions on which they are based.
The reality is that there is simply no evidence to prove that we are any less safe than our colour normal peers. As outofwhack points out, it is nothing more than 'unjust' discrimination.