I've had a few people ask me lately "Why don't you pick on other religions apart from Christianity and Islam? After all, there are thousands you could choose from." Well the answer is pretty simple, but threefold.
Firstly, I live in Australia, which is a predominantly Christian nation. Upwards of 60% of Australians identify themselves as Christians (according to the 2006 census). Most of the first westerners to arrive here were Christian, and that tradition has been carried on from that point onward. Many Christians like to identify Australia as a Christian Nation, while denying the fact that for some 40,000 years previous, the traditional landowners of this country followed their own ancient tradition of storytelling and ritual. And while it is true that our legal system was set up by people who may have been Christian, this does not in fact make our laws Christian laws.I am familiar with the Christian faith, and it is Christianity that I see rammed down the throats of the school children in Australia, not Zoroastrianism or some other faith. This familiarity with Christianity is why they are a topic of many of my criticisms.
Secondly, Christianity is also the largest single religion in the world at around 33%, closely followed by Islam at around 21% (according to adherents.com). This means that just over half of the world is a religious adherent of an Abrahamic tradition. (Note: according to the percentages at adherents.com, "Secular/Nonreligious/Agnostic/Atheist" account for around 16% or people worldwide.) If I were to focus my attention on, say, indigenous Australian traditional religious beliefs, while just as fanciful, I would be only addressing a very small part of the whole.
Thirdly, because the Abrahamic traditions are the most adhered to religions worldwide, their influence and actions are wide and far-reaching. The are in governments and the military, in our schools and in out communities. People in power worldwide subscribe to either one of these religions. Many decisions of political and social importance are made according to, and in the name of, the major Abrahamic religions, and the religions themselves can be seen by many as an extension of patriotism, nationalism and country-hood. Those in power know this and use the emotionally charged religious doctrines to win people over, to urge them to fight to defend their freedoms and their nation from the influences of the "other" religion, depending upon which side you happen to come from.
In the map above we see the relative distribution of Christianity versus Islam worldwide. The Middle-East is obviously the area with the highest level of Islam adherents, and also the place where many of the world's major conflicts are taking place. Christianity, however seems to be more heavily adhered to in South America and Europe than in the "Christian Nation" of the USA, and yet the leaders of the USA still use rhetoric pertaining to "God's will" when invading Middle-Eastern countries on "peacekeeping" missions, when it's pretty clear they are actually after oil to keep the fuel-hungry country afloat.
Of the remaining third of the world that does not adhere to the Abrahamic traditions or secularism, the religions practiced by these people are either of the Asian tradition (Buddhism, Hindu, Sikh, and Chinese Traditional), or are adherents to small and splintered beliefs like Zoroastrianism, Rastafarianism and Scientology. If I were to draw my attention away from Abrahamic traditions, I guess the next biggest target would have to be Buddhism and Hindu, however the countries that predominantly follow these religions are not the ones that wield the balance of power at this time.
So my focus remains on Christianity and to a lesser degree Islam (although some would say that Islam is a far more deserving target than Christianity). To me, however, all religions are as guilty as any other; of indoctrination of children, of willful ignorance about the universe, of sectarian violence and hatred, and of promoting the supposed wants of a higher power over the interests of humanity and the rest of the world.
"The presence of those seeking the truth is infinitely to be preferred to the presence of those who think they've found it." -Terry Pratchett