No matter what our political orientation, we are all environmentalists and the spectrum of our environmental beliefs runs from pale to dark green. The dark green environmentalists are often characterized as zealots.
It is not unfair to assert that many, if not most, who are characterized as environmental zealots use the environment as a Trojan Horse to hide an anti-fossil energy and anti-market agenda. That may seem extreme until you consider the environmental opposition to the Keystone XL pipeline. The opponents simply want it shut down as if that would force Canada not to produce its oil sands that it would be good for the environment, and would have no economic impact.
Canadian oils sands will be produced. The questions are where does the oil go, how does it get to that destination, how is it processed, do the answers have environmental impacts? It is good to remember that actions have consequences.
If the Canadian oil does not come here it will almost certainly go to China. It will be shipped by tanker not pipeline. Although tankers are safe, pipelines have a lower risk and therefore are more protective of the environment. Once in China, it will be processed by their refineries, under their environmental laws. Does anyone think that Chinese refineries meet the rigorous environmental requirements that ours do or that their environmental laws are as protective? So once again, the consequence of environmentalist action of stopping the Keystone pipeline would be less protective of the environment.
Finally, Canadian oil coming here through the pipeline would be a substitute for imports from the Persian Gulf and Africa, which come by tanker. Not only that but the Keystone pipeline would be a benefit to the economy.
There may be some environmentalists who have not thought through the implications of their opposition. But most, especially the well funded advocacy organizations, know exactly what the implications of their actions would be but assign a higher priority to their political agenda.