Magic Magnum said
What exactly would you consider as an example of an extreme atheist/atheist westboro then?
Atheists aren't usually organized well enough to form an organization like a "church" unless they're truly dedicated, BUUUUUT, in theory if they did, the organization would look like this: An atheistic organization that claims to believe that whatever problem of the day is somehow caused by religion, and would picket funerals of victims of tragedies and various religious authorities. They'd hold signs stating things like "Science flies you to the moon. Religion flies you into buildings".
Going more up the scale of violence, you'd get an organization which attempts to censor out any religious speech and execute the religious as dissidents. It would likely resemble the State from the Twilight Zone episode "The Obselete Man". Stalinists would be a real-life example of this line of thinking. It wasn't the only thing they wanted to do, but it was one of their plans to eliminate religion, by very brutal force if necessary.