Gary Milne is a grumpy old man.
This turns out to be The Mother Of All Ironies. Here’s why:
Gary Milne is a dental hygienist by trade hence his job is to help people smile.
Although no one that this author is aware of has seen Gary’s real-life image he certainly does not smile on panel.
This Dental Hygiene Man That Never Smiles hides behind his keyboard.
From behind his keyboard he slings insults at others who do not believe the same Christian Fundamentalist approach to the Scripture Fiction as he does.
And 
this is where he spews his venom from. It used to be such a nice neighbourhood until Darth Dawkins moved in.
[Update July 2018]
Gary Milne, as I now understand the situation, lives in New Jersey. I have been told that he was (perhaps still is) in the Dental Lab business in Kansas.
