|Environmentalism, for example, is something that I suspect everyone naturally supports unless they have some reason not to, and the main reason not to is that it interferes with business interests. So opposition to environmentalism comes mostly from conservative, pro-business parties, while everyone else supports it. It has nothing much to do with egalitarianism.|
But in fact environmentalism has a lot to do with egalitarianism (and with intra-human egalitarianism, not just giving equal rights to nature versus dominating it). In very crude historical terms, there was an initial wave of anti-egalitarian environmentalism followed by a pro-egalitarian wave.
Anti-egalitarian environmentalism is the conservation movement of the late 18th and early 19th century, the domain of Teddy Roosevelt, Gifford Pinchot, and John Muir. To such men, environmentalism was associated with class privilege (preserving nature for the hunting and other recreational pursuits of the gentry and as a resource base for future industry), race privilege (getting rid of those filthy Indians who mess up our pure wilderness), and male privilege (wilderness pursuits as a school of tough manly virtue, a la the Boy Scouts). Indeed, there was significant crossover between supporters of early environmentalism and anti-egalitarian causes like eugenics (Hitler was, after all, a vegetarian and a conservationist). This anti-egalitarian strain explains the initial hostility of the socialist left (the infamous "red-green" battles). It wasn't just (as a common green view similar to Drum's holds) that socialists were aiming at an industrial communism that would be equally threatened as private enterprise by environmental protection.
The second wave of environmentalism -- which came to prominence as "environmentalism" in the 1970s, though it has a much longer history -- started down a more egalitarian path. Pollution issues disproportionately impact oppressed people. Increased respect for other cultures brought with it a valuing of their comparatively more sustainable lifestyles. On the far left, recognition of the destruction caused by capitalist development programs began to note the environmental factor, as third world peoples' livelihoods are undercut by degradation and loss of resource access. Rhetoric of "exploitation," "rape," and "dominance" convey the egalitarian thinking in modern environmentalism. Indeed, even the environmentalist conservatives of today -- notably "sportsmen" (hunters and anglers) and "creation care" evangelical Christians -- generally hold a comparatively egalitarian/populist outlook (today's hunters focus on preserving access to wildlands for the people against the depredations of big government and big business, and the new wave of evangelicals are more concerned about poverty and less concerned about homosexuality than their forebears).
This is not to say that egalitarianism is a complete explanation for environmentalism (or any other social movement), or that modern environmentalism is fully egalitarian (the environmental justice movement still has complaints against the big green players). But it does challenge the view proposed by Drum (and by a number of green theorists) that environmentalism is unique from other political issues.