You have another inconsistency as well. As you should have noticed in the "How many" thread, the assumptions that lead you to believe that failures of the LHC are evidence that it would destroy Earth are the same ones that lead you to believe that annihilational threats are irrelevant (after all, if P(W|S) = P(W), then Bayes' rule leads to P(S|W) = P(S)).

Thus, given that you believe that failures are evidence of the LHC being dangerous, you shouldn't care. Unless you've changed to a new set of incorrect assumptions, of course.