I don't know about most of that because I've never run into whole groups of people like that but I'm sure there are some out there. But I will say that shooting film - especially with some of the older film cameras - requires a higher degree of skill than digital. You can't easily just go into post and bump up the exposure. 800 ISO is about the max you get for useful shots. You can "push" film but the result is often much less pleasant than pushing a digital camera a stop. If you think dynamic range is bad in a DSLR, try shooting Kodachrome.
And if that wasn't enough, you lose the ability to chimp as well. The shot is what it is until you get the film developed and proofed.
Still, over many years I was able to develop a knack for determining exposure without the meter. Most of the time, I could select an aperture and shutter combination based on the film I used in a natural lighting environment and get it right. Sure I was often off by +/- 1/3 stop and occasionally even a full stop. But for the most part I would get it right. Of course when it was critical I would use a meter. But it's amazing how quickly you learn exposure when it costs you the shot and $20 every time you get it wrong.
Anyone who has learned these skills over many years of trial and error is bound to develop a sense of pride. This can lead to seeing people who shoot auto-ISO, program and green box as inferior. They will likely see others who may shoot manual but only after chimping a dozen times to get the exposure right as equally inferior.
I'm sure it is easy to fall into the ego trap because it is difficult for some to realize that each person is on their own path with their own agenda and their own ideas on what is important. Some will get vocal about people who do things differently but these will likely be younger people who have self-esteem issues and their entire self-image revolves around this idea of themselves that the things that they do are the important ones (to them of course) and that they are good at them.
And I'm sure these people gravitate towards one another, stroking each others' egos as well because nothing feels better than outside confirmation that your ideas are right. That's why boards like this exist. That's why facebook grew so huge so fast. And as human beings, none of us really enjoy stepping too far outside our comfort zone. Ego stroking is a basic need. It's not just human. It extends to other primates as well. Some need it more than others and some need to be jerks to others to get that. Some get it from putting others down while others get it from lifting others up, but we all need it and obtain it in some minor way.
So I guess the point is - neither you nor I are exempt from the feelings and conditions that cause people to be like that. We just deal with it in different ways in different areas. Rather than griping about how other people on another board are "uptight", find yourself a board where you feel welcome and stay there.
I can see most of them are very knowledgeable and probably at one time working as a pro but the digital revolution put them out of work. It was sad. Could you imagine you didn't get your contracts because you are shooting with a Nikon??? And you have to deal with all the Canon pros who just stole your jobs???