How to explain individual ignorance towards people wanting to help?
Different personalities at play can partly explain this.

An old joke goes:


  "There are two kinds of people in this world. If there is an electrical fence, and you tell them about it, one will believe you. The other will insist on peeing on the fence to find out the truth."


Individuals prone to anxiety may indeed be less trusting. 

Trusting someone's word, especially a stranger's, carries uncertainty and uncertainty to an anxious mind causes a lot of mental distress. So anxious people often try to cope with this by trying to regain the feeling of being in control by "doing their own research". 

A narcissist personality type may have an unrealistic view of their status in society and thus expect to be treated differently than "normal" folks. Due to their exaggerated sense of importance of their own self, they may feel that regular rules don't apply to them.

A paranoid personality type would be less trusting of a stranger too, as they sometimes tend to be overly suspicious and distrustful of people. 

(These are the few personality types that immediately came to my mind and their underlying way of thinking could explain why these kind of people may have opted to not listen to your group of "peace-keepers").