Okay, but this seems to violate conservation of expected evidence.

No it doesn't.

Either you can be depressed by the answer "we're all going to die" or, less plausibly, by the answer "Everything is going to be fine", but not both.

I only suggested the latter, never the former. I'd be encouraged if the AI researchers acknowledged more risk. (Only slightly given the lack of importance I have ascribed to these individuals elsewhere.)