Given that this was the scientific consensus, "the competence of scientists that they make that mistake" compared to whom? Laymen? I'd still bet on the scientists.

If there's a real concern is not about "the competence of scientists that they make that mistake", but about the certainty of our grasp of the scientific facts in general.

It's not that those scientists were incompetent.

It's more like "science in general doesn't know as much as solidly as we'd like to think" about the matter.