Yes, I agree that if a politician or government official tells you the most effective thing you can do to prevent asteroids from destroying the planet is "keep NASA at current funding levels and increase funding for nuclear weapons research" then you should be very suspicious.
I think you're missing the point; I actually do think NASA is one of the best organizations to handle anti-asteroid missions and nukes are a vital tool since the more gradual techniques may well take more time than we have.
Your application of cynicism proves everything, and so proves nothing. Every strategy can be - rightly - pointed out to benefit some group and disadvantage some other group.
The only time this wouldn't apply is if someone claiming a particular risk is higher than estimated and was doing absolutely nothing about it whatsoever and so could...
My friend, hearing me recount tales of LessWrong, recently asked me if I thought it was simply a coincidence that so many LessWrong rationality nerds cared so much about creating Friendly AI. "If Eliezer had simply been obsessed by saving the world from asteroids, would they all be focused on that?"
Obviously one possibility (the inside view) is simply that rationality compels you to focus on FAI. But if we take the outside view for a second, it does seem like FAI has a special attraction for armchair rationalists: it's the rare heroic act that can be accomplished without ever confronting reality.
After all, if you want to save the planet from an asteroid, you have to do a lot of work! You have to build stuff and test it and just generally solve a lot of gritty engineering problems. But if you want to save the planet from AI, you can conveniently do the whole thing without getting out of bed.
Indeed, as the Tool AI debate as shown, SIAI types have withdrawn from reality even further. There are a lot of AI researchers who spend a lot of time building models, analyzing data, and generally solving a lot of gritty engineering problems all day. But the SIAI view conveniently says this is all very dangerous and that one shouldn't even begin to try implementing anything like an AI until one has perfectly solved all of the theoretical problems first.
Obviously this isn't any sort of proof that working on FAI is irrational, but it does seem awfully suspicious that people who really like to spend their time thinking about ideas have managed to persuade themselves that they can save the entire species from certain doom just by thinking about ideas.