Not really an expert on human psyche or anything, but I'll take a crack at it:
Perhaps it is because we are not all subject to the same life experiences. Some people are subject to lives that leave them with little to no self-confidence or ability to act with assertion. Others have those abilities, and in situations that require that action be taken, humans tend to get behind those with such abilities since they tend to be the skills required to handle such conditions (as opposed to, neurotic behavior and indecisiveness).
I could be wrong, though.
