I'm sure you can see why "many of us are more concerned than we can publish" could be read as alluding to secret knowledge.

The problem with the argument is, well, why doesn't this apply to everything? Massive changes happen all the time in the world, and anything could be a disaster if our only standard for "could" is lack of knowledge that it won't be. If someone said "we need to focus our global efforts on stone-faced office buildings, because humanity might go extinct if we keep building so many all-glass ones", we'd demand more than a lack of evidence.