Militant atheists tend to embody anti-theism. It typically manifests as active desire to dissuade anybody from holding religious beliefs or performing religious practices.

Any clergy, whether faithful or secular, has the capacity to act in a militant fashion.

I don't read this as he thinks all Atheists are militant, but that his own behaviour was obnoxious? If so, many of us have met those.

It's nice to hear about someone who can change their mind so completely; the trick is not to swing to the other end of the spectrum, trading one absolute for another.

yes, and obnoxious too. You should have seen me.