> I'm asking why anyone else listened to them on this topic alone

First, it wasn't this topic alone; whaling too. You also don't need 100% of people to listen. You just need to shift from 45% to 55%. If people were already skeptical about nuclear because they conflate nuclear weapons and nuclear power, then they only need to shift ~10% on the issue. And money gets their message out much stronger.

> That had the double benefit of keeping their hands clean while discrediting future environmentalists.

Washington State had I-732, which would make taxes less regressive and efficiently tax carbon. Both issues liberals pretend to care about. Most state environmentalist groups fought against this! It got defeated because of that opposition, then those groups put up a different carbon tax initiative which would funnel the money to them to spend as they want. Also shot down with a shift of who voted for and against. Environmentalists are sometimes the villains.