The majority of religions are not exclusive to all other beliefs. Even christanity isn't. The actual wording in the bible is basically that you won't worship other gods, not that other gods don't exist...
Believing in one religion does not require disbelief in all others, only that you follow one in preference to the others.
And that's without mentioning that the big three religions all worship the same god anyway.
I'm pretty sure those holy wars. jihad etc are not fought over nothing.
There are fundamental differences between the religions, no-one is denying this. You may be able to worship one god and give "lip service" to the other gods, what I am saying is that there isn't any way to justify one over another, except on "personal grounds". And these personal grounds usually are
a) You were brought up that way
b) You like Tom Cruise
c) You like the ceremonies
etc etc.
What I'm saying, is that whilst Atheism seems to be under attack from every religion "because we deny you religion", it seems perfectly ok for every religion to go on playing "happy families" with those around them. No-one ever calls you up on it.
And it is this lack of judgement that is entirely irrational. If you ask yourself "why do I believe X, Y, Z", try to ask yourself, how much of that is entirely irrational, circumstantial, etc. And how much is entirely justifiable.
Because
a) I was brought up as X may be understandable, but not justifiable
b) It says so in this book that I must believe in X is understandable, but not justifiable
c) I just think so is irrational, and not justifiable.