I don't think Nick made a good case as to why these movements / belief systems deserve to be call "scams" and more importantly deserve to be ignored (in favor of "spending more time learning about what has actually happened in the real world"). The fact that certain hopes and threats share certain properties (which Nick numbered 1-3 in his post) is unfortunate, but I didn't find any convincing arguments in his post showing why these hopes and threats should therefore be ignored.
(My overall position, which I'll repeat in case anyone is curious and doesn't want to dig up my past comments, is that Pascal's Wager is a difficult unsolved philosophy problem, whose solution probably requires a great deal of progress in decision theory (e.g., how to handle logical uncertainty and deal with running on unreliable hardware) and ethics (e.g., how much utility should I really assign to certain outcomes). In the face of such philosophical uncertainty, my instinct is to spend a portion of my resources on the philosophical problem itself, a portion on the most promising "wager", and the rest on other more mundane priorities. I don't have a good argument for why this is the right (or rational) thing to do, but neither do I see any good arguments against it.)
Nick Szabo on acting on extremely long odds with claimed high payoffs:
Beware of what I call Pascal's scams: movements or belief systems that ask you to hope for or worry about very improbable outcomes that could have very large positive or negative consequences. (The name comes of course from the infinite-reward Wager proposed by Pascal: these days the large-but-finite versions are far more pernicious). Naive expected value reasoning implies that they are worth the effort: if the odds are 1 in 1,000 that I could win $1 billion, and I am risk and time neutral, then I should expend up to nearly $1 million dollars worth of effort to gain this boon. The problems with these beliefs tend to be at least threefold, all stemming from the general uncertainty, i.e. the poor information or lack of information, from which we abstracted the low probability estimate in the first place: because in the messy real world the low probability estimate is almost always due to low or poor evidence rather than being a lottery with well-defined odds.
Nick clarifies in the comments that he is indeed talking about singularitarians, including his GMU colleague Robin Hanson. This post appears to revisit a comment on an earlier post:
In other words, just because one comes up with quasi-plausible catastrophic scenarios does not put the burden of proof on the skeptics to debunk them or else cough up substantial funds to supposedly combat these alleged threats.