I don't think GP is dismissing the scenarios themselves, rather espousing their belief these answers will do nothing to prevent said scenarios from eventually occuring anyways. It's like if we invented nukes but found out they were made out of having a lot of telephones instead of something exotic like refining radioactive elements a certain way. Sure - you can still try to restrict telephone sales... but one way or another lots of nukes are going to be built around the world (power plants too) and, in the meantime, what you've regulated away is the convenience of having a better phone from the average person as time goes on.

The same battle was/is had around cryptography - telling people they can't use or distribute cryptography algorithms on consumer hardware never stopped bad people from having real time functionally unbreakable encryption.

The safety plan must be around somehow handling the resulting problems when they happen, not hoping to make it never occur even once for the rest of time. Eventually a bad guy is going to make an indecipherable call, eventually an enemy country or rogue operator is going to nuke a place, eventually an AI is going to ${scifi_ai_thing}. The safety of all society can't rest on audits and good intention preventing those from ever happening.