Wells's book: Apocalypse when.

I took a quick skim through the book. Your focused criticism of Wells's book is somewhat unfair. The majority of the book (ch. 1–4) is about a survival analysis of doomsday risks. The scenario you quoted is in the last chapter (ch. 5), which looks like an afterthought to the main intent of the book (i.e., providing the survival analysis), and is prepended by the following disclaimer:

This set serves as a foil to the balanced discussions by Rees, Leslie, Powell, and others. The choice of eight examples is purely arbitrary. Their purpose is not orderly coverage but merely examples that indicate a range of possibilities. The actual number of such complex unorthodox scenarios is virtually infinite, hence the high risk.

I think it is fair to criticize the crackpot scenario that he gave as an example, but your criticism seems to suggest that his entire book is of the same crackpot nature, which it is not. It is unfortunate that PR articles and public attention focuses on the insubstantial parts of the book, but I am sure you know what that is like as the same occurs frequently to MIRI/SIAI's ideas.

Orthogonal notes on the book's content: Wells seems unaware of Bostrom's work on observation selection effects, and it appears that he implicitly uses SSA. (I have not carefully read enough of his book to form an opinion on his analysis, nor do I currently know enough about survival analysis to know whether what he does is standard.)