Nobody taking them seriously is the only way to stop them. Compare with people starting to take them seriously, which brought us at least three country-destroying wars, trillions of dollars of waste, and the erosion of citizen rights in the whole western world - all within last two decades.
> remember what happened last time nobody took them seriously? a generation of conspiracy nutters was born.
I think that it's my fault, but I honestly don't know what you're referring to. 9/11? The Kennedy assassinations? In any case, how does not taking terrorists seriously create conspiracy theorists?
That's because if you are ever disproved, you lose credibility for future claims.
That's orthogonal to the merit of using such "mundane-looking" tactics and then rightfully claiming involvement.