The moral wording of their argument, the appeal to morality, comes simply from an understanding of risk management. Risk being directly proportional to both the

The moral wording of their argument, the appeal to morality, comes simply from an understanding of risk management. Risk being directly proportional to both the probability and to the impact of the event. The higher the stakes the less you want to take the risk, even in a potentially low probability occurrence. Most people wouldn't think twice about walking along a garden wall if it were only a foot above the ground. If it were on the edge of a thousand foot drop, only a daredevil would attempt it. In this case however, we are talking about (and I apologise for the tired cliché) walking a tight-wire over a thousand foot drop. It is likely, and the consequences are most likely fatal. In this sense, it is entirely reasonable for a person or a group, on the strength of their conviction, to use strong moral language to hopefully avert the untimely deaths of millions, and understandable to attribute immorality to those who would continue to participate in the activities which they believe would cause these deaths. Is that language effective? Probably not.. but what else do you do to convince a population who absolutely do not want to be convinced. And, sure there is no scientific consensus on the science. Never is.. never has been. There is, however, consensus on the risk management.