> Relatedly I've been thinking about how to compare the moral culpability of anti-nuclear activists for climate change to that of oil companies. Are sins of preventing beneficial action comparable to sins of taking harmful action? Do intentions offset effects?

Seems like knowledge could come into play here. Someone could have made the same argument about coal 150 to 200 years ago because the data didn't yet exist to suggest it was harmful. From their perspective, coal could have looked better than the alternatives. Not sure how culpable activists would be in that scenario, at least relative to fossil fuel companies of today which deliberately release disinformation to their own benefit.