Like it or not, the human race has a tendency towards tribalism - we can see that in a long history of brutal ethnic wars around the world. But the tendency also rears its heads in supposedly virtuous pursuits where those who see themselves as the inner priesthood raise barriers - using linguistics, dogma or people's background.
The environmental movement is as guilty of raising those barriers as anybody else. We read about 'endosymbiotic thrivability'. 'mindfulness' and 'eco-centric world views', we are told we must be against fracking, GM, nuclear - and capitalism in general, and I spent my early days in the movement dodging the question of where I did my degree (Cambridge) or where I worked previously (the Ministry of Defence) - as those answers dropped me a couple of places down the rankings of the self-righteous.
None of this snobbery is helpful in any way. We can sit on our self-built pedestals, sneering at those who 'don't get it' or we can get down amongst ordinary (and I mean that as a compliment) people going about their daily routine and help them 'get it'. Only one of those strategies will deliver sustainability - and it isn't the one occupied by those who think they are morally superior.
So my third rule of pragmatic environmentalism is:
No inner priesthood: we have to make sustainability relevant to others, not bend them to our will.
In other words, if people want to find out about environmental issues and what they can do to help, they should be welcomed with open arms - not subjected to some kind of initiation test. If they don't 'get it', then it is our fault for not making it understandable, not theirs.