There are a bunch of physicists signed up on there; (e.g. Martin Rees) - they don't seem relevant to it at all. There's been a long history of famous physicists weighing in on entirely unrelated things.
Musical artist Grimes is also a signatory. It would seem the real purpose of this is to train an AI agent on appeal to authority.
I hope the real purpose is to train an AI agent to understand why appeal to authority was always cosidered to be a logical fallacy.