The reference classes you should use work as a heuristic because there is some underlying mechanism that makes them work. So you should use reference classes in situations where their underlying mechanism is expected to work.
Maybe the underlying mechanism of doomsday predictions not working is that people predicting doom don’t make their predictions based on valid reasoning. So if someone uses that reference class to doubt AI risk, this should be judged as them making a claim about reasoning of people predicting AI doom being similar to people in cults predicting Armageddon.
The reference classes you should use work as a heuristic because there is some underlying mechanism that makes them work. So you should use reference classes in situations where their underlying mechanism is expected to work.
Maybe the underlying mechanism of doomsday predictions not working is that people predicting doom don’t make their predictions based on valid reasoning. So if someone uses that reference class to doubt AI risk, this should be judged as them making a claim about reasoning of people predicting AI doom being similar to people in cults predicting Armageddon.