There is a very important role that anger, ridicule and passion play in any social movement. While intellectual understanding is key to a movement that is well-grounded, it is the primary emotions that provide the impetus for social organization. Without this, atheism would simply remain an idea to be discussed in academia and in private settings.
Let me give you an example. Secular Humanism has been around for more than a century. Humanists often deride the ‘New Atheists’ for their bitterness. In fact, the argument from many humanists has been that their tactics are more effective! But how many people knew about secular humanism before the ‘New Atheists’? Their whole movement was an academic one, restricted to an elite group of people who had the time and inclination for such intellectualisms. While the humanists were debating about human rights and ethics for over a century, atheists continued to remain in the shadows, in a cultural environment where they were unable to realize many of their fundamental rights. The only community that was available to most atheists was society at large. As you may well know, one of the most important functions of religion is to provide a common cultural ground to enable a common morality and social code to bring together people and form a functioning and content community. We atheists did not have this- not until a few years ago. It is easy to ignore the freedoms (from the point of view of social acceptance) we have gained towards expressing our beliefs in public and for gathering in the name of reason. It is easy to forget that millions of atheists crave the kind of social contact that religions have traditionally provided. It is even more easy to forget the role that anger, ridicule and passion have played in creating this global community of freethinkers. Without the ‘new atheists’, secular humanism would have remained irrelevant in the public sphere. Today we can meaningfully talk about replacing religion with a secular morality derived from humanistic principles only because of the social impetus that the ‘New Atheists’ like Dawkins have provided humanity with.
I also recommend this recent article by a group of the Nirmukta writers. He was one of us. We are now diminished.