GM crops should have been welcomed by environmentalists. That they aren't betrays their knee-jerk response to corporations and anti-globalization links.
Moderate Environmentalists are working from an idea that the ideal population of North America would be less than 5 mil and they are determined to achieve that very soon. The extrtemists among them believe in Human Extinction but insist that everyone else has to be extinctified first after which they will consider offing themselves. Actually they are kind of walking the walk in that they are very big on aborting their children, but it is slower than the prefered famine or pandemic.
Nuclear energy should have been welcomed by environmentalists if one thinks they are actually interested in untouched-by-humans wilderness and natural stuff.But that is not their goal. Most of them are displaced Communists who found it inconvenient to remain nominal Communists after the Stalinist Utopia disutoped. The purpose of Environmentalism is to get control of everything for the Vanguard of the Masses and prune back the human population to make total control more manageable.