

I find this argument very strange, though not unfamiliar.

An analogy someone used a while back can perhaps illustrate it.

Say, for example, there are people living on a volcanic island, and a group 
of geologists determine that a volcano is imminent. They warn the people on 
the island that they are in danger, and should leave. A group of people on 
the island is given the task of warning others of the danger.

They believe the danger is real, but others may not. 

Does that mean that the first group are NECESSARILY arrogant in warning 
others of the danger? Does it mean that they are saying that their beliefs 
are correct, and all others are false?

Some might indeed react to opposition with arrogance, and behave in an 
arrogant manner, but that is a personal idiocyncracy. It does not 
necessarily mean that they are all arrogant.
