Sure, there's definitely some Gaia-worshipers here and there, but you're miscasting the environmentalism movement if you think they're a majority or even a driving force. I'd place the driving forces as first some sort of rational self-interest -- if your house is on fire, you don't need to worship the house to want to put out the fire -- and second as some sort of combination of a sense of stewardship and guilt, stewardship, a need to protect and care for things, and guilt at taking what we feel isn't ours. The guilt might blend into Gaia-ism, but I don't think it must.