Granted, a religious ideology is usually based around some kind of 'holy' teachings that originate with a 'deity'. Beyond that, however, is there any real difference with how a religion affects the world - politics, culture, public debate, individual participation in the group, freedom of thought and speech, etc?
For me, I see Communism as a religion and not representative of atheism at all. It may, technically, be atheistic in that is not centered around a deity, per se. But it does deify the party and use techniques to enforce the 'will of the state' that were perfected centuries ago by the Catholic Church. The word 'propaganda' was, literally coined by the Church.
Personally, when it comes to individual beliefs - I am a staunch pluralist. I think that is a perfectly reasonable stand. As with atheism, pluralism barely merits the 'ism' - in fact, it is somewhat 'anti-ismic.'
Nevertheless, I am strongly against the stifling group think that all ideologies foster, by definition. In many cases, I feel that most of the more successful ideologies have proven to be dangerously detrimental to human progress and the health of the planet itself.
Therefore, I am insulted when people refer to anyone as an 'atheist leader'. This perpetuates the false notion that there is an atheist 'movement' that conforms to some common ideology and can be 'led' solely based on a single common factor of non-belief.
For example, in some ways, I think Hitchens is brilliant and in others - a pure jackass. I share his atheism, his vocal disapproval of the 'poison' of religion. But the nature of his support of the Iraq war is bullshit. Interestingly, I think he is probably much more anti-ismic than many of his 'followers.'