Fundamentalist Atheists.

beliefnet
There are two types of atheists that seem to acquire the label fundamentalist. 
One type insists that insists that to be an atheist one must refuse to accept a supernatural god in any way, shape, or form.  No nuance permitted.  A-theist: No god. No discussion.  

The other type insists that any type of religious teaching is abuse. 

Both types are relatively rare, but like all fundies are certain that they are right and are not shy about promoting their cause. Preaching to their choir and accepting the flak from those they are preaching against is one of the few ways to acquire fame and fortune as an atheist. 

Most atheists don't have congregations or PACs for support as most atheists are too busy quietly making a difference for their family and friends by competing in a religion dominated world.  In this sense they have a common cause with the quiet feminists, and other minorities who simply are so competent that they can succeed without connections.  As some woman who broke the glass wall into a male dominated profession noted, in order to succeed in this business you have to be twice as good as the average (white) male.  Fortunately this is not difficult.  Atheists are generally better educated, more flexible and rational in their thought processes, and less dependent on networking.  As a result if competence is a virtue and it usually is they can usually make a difference.  Also like religious minority groups they tend to seek out professions where competence is both measurable and rewarded.  STEM, arts, academia, medicine, and finance.  

Since they usually do well in these important professions, it is yet another reason they are hated.