So, what is a religious atheist? A religious atheist is simply a person who ‘believes’ in atheism. They ‘believe’ in the non-existence of God, and any other similar causal entities. I am terming these things ‘belief’ because a religious atheist goes about talking of his non-belief in God, yet is often not aware of the cosmological and ontological arguments regarding that particular topic. A religious atheist disbelieves in God simply because that is their belief. These people piss me off, and are just as bad as any Christian. They have never heard of an ontological or cosmological argument, have no idea who Thomas Aquinas or Friedrich Neitzsche are, yet they go around acting like they are some how above anyone who is religious, when, in reality, what they are following is a religion. The religion of unfounded, logically unsupported, atheism.
To clarify, if you believe nothing exists, it is still a belief. If you can prove that it is an improbability nothing exists, and then judging based on those chances, then it is not. That is what separates the true atheists (who are always willing to embrace logic, no matter what it attempts to prove) from the religious atheists, who are just dumbfucks.
There is a lot that is wrong in the above, yet the core message seems to me to be accurate. First, it's inaccurate to call an atheist "religious" simply because they don't think very much about arguments for and against the existence of gods. A genuinely religious atheist is someone whose atheism is part of their religion — Raelians, for example. Logically unsupported atheism is no more a religion than logically unsupportable disbelief in anything else. Gregorius is describing irreligious atheists who don't care enough about the subject of gods to work through various arguments. They're apathetic atheists, not religious atheists.
It's also a mistake to insist that atheists who work though the arguments and logic are somehow "true" atheists while everyone else isn't. That's a No True Scotsman fallacy which assumes that there is something more to atheism than merely disbelieving in gods. There isn't. Atheists who spend a lot of time working through theological and atheological arguments may be better educated atheists, but they aren't "true" atheists. It doesn't even mean that they are more intelligent atheists — being apathetic about theological argument doesn't mean you're dumb because you may feel that you have more important things to worry about.
Where the real problem exists, and which I think Gregorius is hitting on, is with atheists who don't actually know much about theological arguments, don't known much about logical arguments, and don't know much about philosophy in general, but they proceed to act like they are superior to theists merely because of their atheism. Such atheists will try to engage theists in an argument but then do a very bad job of it — often without even realizing how badly they are doing. They commit one logical fallacy after another, make one bad argument after another, and in the end continue to insist that it's the theist who doesn't know anything.