In the OP, Stringsinger asked some questions, hoping to relieve Mudcat of the topic for some time. I would like to endorse this heroic goal, so here is my Q&A version:

Is militant atheism a religion? No; neither is militant polytheism. (To be a religion, some more specific content is required, though not necessarily a god or a holy book or praying.)
Are militant atheists militant? Yes.
Are militant atheists as militant as militant polytheists? Some are, some are more, some are less so.
Is atheism a special source of militance? No, ideologies are, whether atheist, religious, or other.
Is militance against other militance/militants justified? Only in rare cases.
Is an ideology justified if it propagates justified militance against other militants? Not by that fact alone.
Do atheist and religious militant ideologists of have things in common, such as saints? Frequently, though interpretations usually differ from one ideology to the other.
Should missionary zeal be limited by law? Yes, in the widest possible limits.
Should deriding other ideologies be forbidden? No, but reasonible persons should strongly discourage it, even if they share the deriders' criticism.
Can a state be neutral in ideological matters? Not really, but it should try.

Glad to be of service.