True, the availability heuristic, which the quote condemns, often does give results that correspond to reality - otherwise it wouldn't be a very useful heuristic, now would it! But there's a big difference between a heuristic and a rational evaluation.

Optimally, the latter should screen out the former, and you'd think things along the lines of "this happened in the past and therefore things like it might happen in the future," or "this easily-imaginable failure mode actually seems quite possible."

"This is an easily-imaginable failure mode therefore this idea is bad," and its converse, are not as useful, unless you're dealing with an intelligent opponent under time constraints.