What about anti-religious fanatics? Who just in the last century murdered more people than everybody else in entire history?
The Greek gods are just as valid - its all fantasy.
Even Greek pagan gods were something much more profound than a fantasy. I find your view to be barbaric and yes - fanatical. This is one step from Bolsheviks turning churches into stables, cinemas, beer pubs, museums of science and religion or Taleban destroying statues of Buddha.
Religious differences are a major cause, if not The major cause, of wars.