Many experts in a field used to agree that the world was flat. That worked out well. You seem to think that continuity of thought or people being agreeable is some sort of characteristic of undeniability. I simply do not subscribe to that belief.
Quite simply, experts can be as wrong as anyone else. A group of experts doesn't change that.
First, that is a common misconception that anybody seriously thought the world was flat. Certainly some people did, and some probably still do. But, it was never a widely-held belief. Certainly not the 'experts' - whomever they may have been (sailors?).
Experts can be wrong, but not as wrong as anyone else. Again, that is why they are experts. Otherwise we should all quit our respective careers. For example, an expert should have 95% confidence in whatever they are doing, and 'anyone else' would have lower confidence limits. Otherwise that 'everyone else' would be an expert. Again, experts can and are wrong but not to the same degree.
Here is a nice little experiment: get 100 PhD's and put them in an auditorium. Now yell fire and watch what happens. Now do the same thing with a bunch of high school graduates and see what happens. Point is, one PhD can be smart but combining 100 of them doesn't make them any smarter.
If those 100 people have PhD in fire or disaster management - i.e. they are subject matter experts in that field - then it should be reasonable to expect different reactions than non-expert high school graduates. Assuming those high school graduates aren't (e.g.) firemen themselves (i.e. subject matter experts).
Also, putting 100 subject matter experts together does make them 'smarter' (again with the quotes because I am not sure exactly what 'smarter' means here); contrary to popular belief about herd mentality. The notion of one lone inventor coming up with the next big thing is a fallacy. Most break-throughs are by collaboration.