It is not an overwhelming mentality.
There are a number of people with an irrational fear of human interaction.
Fear will make people express their opinions very loudly and strongly.
There is absolutely no way to entice these people to play open and they would absolutely quit the game if they were forced to, so they should be left alone to play in their solo or group modes.
The issue is them transmitting their fear to others with their loud, strong and baseless opinions.
The way this game is designed griefing is utterly impossible.
Not sure where you are getting this information, seems you are just pulling it from a well of wishful thinking, but you are actually quite wrong. It has been shown time and again that games with pve only options are more successful than games that are pvp only. It has been shown time and again that if you give people the choice between a pve server and a pvp server the vast majority are going to play on the pve server. I have no fear of human interaction at all, I quite enjoy it actually, I just don't have any interest in human interaction that involves them shooting at me. Fear doesn't enter into the equation, its just not fun, and at the end of the day fun is the only reason I am playing a game.