Justifiable, no, but cause for further testing and research.
...Research that they are very unlikely to do because they've already claimed it as safe, and unless something makes them (like people not taking it up, or suddenly people start getting very sick and they can't somehow find a way to refute it as just being just coincidence) they most probably wont ever do any.

Have you ever watched Fight Club?
A new car built by my company leaves somewhere traveling at 60 mph. The rear differential locks up. The car crashes and burns with everyone trapped inside. Now, should we initiate a recall? Take the number of vehicles in the field, A, multiply by the probable rate of failure, B, multiply by the average out-of-court settlement, C. A times B times C equals X. If X is less than the cost of a recall, we don't do one.
Similar sentiment really...