Thinking about it I look at it this way: -
There are at least two distinct and separate aspects to the workings of the industry (and others) that may not be evident in others.
Customer Service
The speed of the check in, the quality of the service, the problem solving with customer complaints relevant to these issues, the comfort level on board, the time keeping, the getting you to the destination on time.
This is also the bit that airlines/staff can influence easily
This, from memory, is often the area where positive posts appear.
But, and this is a big but, often staff directly involved are not empowered by their employers to resolve matters instantly. Though sometimes they can (see the post regarding the boarding card mix up)
Flight safety and operations
This is the bit that is governed by legislation, safety culture, operational training and knowledge.
It seems that a lot of the sharp replies appear in this area
It seems that a lot of the arguments occur in this area
It seems that a lot of untrained posters try to influence this area (that is not to say they don't have some knowledge)
As an example, whilst the mobile phone argument is undecided by the legislators, no amount of I know better, I'm a mobile phone expert etc. can change an individual airlines approach to this matter.
This bit will, in some cases I guess, will require international changes to legislation - not easy for an individual or airline to influence.
But this is the bit that causes the most grief.
You can see the arguments that are ongoing, you can also see some of the "off-beat" comments that seek to stir up trouble, you can see the "I demand an answer to this question" (in one case recently that answer had been given).
As a case in point the flaps/slats arguments.
Think it through; to be effective, every airline in the world would have to change their procedures, they would, I assume, have to have regulatory permission to do so, they would as part of that process have to prove that it would overall improve safety (OK it would prevent 2 or 3 accidents over a long period) but, in reality, I don't think a nil accident rate is actually achievable in a lot of industries.
but that is a matter for the regulators to address, not individual airline staff.
So I can see a lot of frustration in replies when, often, the same technical reasons are being given but often are still met with "but I know better that the industry attitudes".
Bear in mind also that in a lot of cases the persona you see on these forums is NOT the actual persona of the individual!
To recap, do not confuse customer service related issues with technical issues - they are poles apart.