First, let me say I agree with JP.
Although you expected as much from me, to which I am not sure if this was denigration or a show of superiority, I am still at a loss on your choice of words and thinking stewards of the environment are classified with terms such as "superiority".
From the same dictionary you used "The free dictionary" I find.....
Noun 1. superiority - the quality of being superior or high qualitycaliber, calibre, quality - a degree or grade of excellence or worth; "the quality of students has risen"; "an executive of low caliber"
choiceness, fineness - the quality of being very good indeed; "the inn is distinguished by the fineness of its cuisine"
first class - the highest rank in a classification
first water - the highest quality gems
ingeniousness, ingenuity, cleverness - the property of being ingenious; "a plot of great ingenuity"; "the cleverness of its design"
low quality, inferiority - an inferior quality
2. superiority - the quality of being at a competitive advantagefavorable position, favourable position
advantage, vantage - the quality of having a superior or more favorable position; "the experience gave him the advantage over me"
edge - a slight competitive advantage; "he had an edge on the competition"
inside track - a favorable position in a competition; "the boss's son had the inside track for that job"
upper hand, whip hand - position of advantage and control
3. superiority - displaying a sense of being better than others; "he hated the white man's superiority and condescension"arrogance, haughtiness, hauteur, high-handedness, lordliness - overbearing pride evidenced by a superior manner toward inferiors
4. superiority - the state of excelling or surpassing or going beyond usual limits
Onto itself, I find no definition of superiority that would cast a negative on stewards on general terms. Certainly there are arrogant people in every corner of social groups.
I think you used a term to make a point, but is way off topic.
I understand your points trying to be made. I think perhaps you are trying to make some comparison of those environmentalist and others who think they know better than others, demand from others by zoning and codes designed to "save ourselves", and everything else that limits freedom.
But being a good steward of the earth, or anything else, does not automatically assign "superiority". You can be in charge of your own backyard (being a steward of your property) without negative connotations being thrown that you are superior to another person.
I do not like environmental extremists and social justice folks. But I think there are many more good stewards of the environment, including hunters, backyard gardeners, beekeepers, and nature loving folks...who display no "superiority" qualities that you suggest. Being a good steward is one thing. Being an arrogant, controlling jerk who wants to tell others how to live, is quite another.