In response to the ongoing debates arguing for the essential oneness or compatibility of all religions, this essay makes for an interesting read.

http://www.dharmacentral.com/universalism.htm

Some highlights:

"Of the many current peculiar concepts mistakenly ascribed to Hindu theology, one of the most widely misunderstood is the idea that Hinduism somehow teaches that all religions are equal…that all religions are the same, with the same purpose, goal, experientially tangible salvific state, and object of ultimate devotion. So often has this notion been thoughtlessly repeated by so many - from the common Hindu parent to the latest swamiji arriving on American shores yearning for a popular following - that it has now become artificially transformed into a supposed foundation stone of modern Hindu teachings. Many Hindus are now completely convinced that this is actually what Hinduism teaches. Despite its widespread popular repetition, however, does Hinduism actually teach the idea that all religions are really the same? Even a cursory examination of the long history of Hindu philosophical thought, as well as an objective analysis of the ultimate logical implications of such a proposition, quickly makes it quite apparent that traditional Hinduism has never supported such an idea.
The doctrine of what I call "Radical Universalism" makes the claim that "all religions are the same." This dogmatic assertion is of very recent origin, and has become one of the most harmful misconceptions in the Hindu world in the last 150 or so years. It is a doctrine that has directly led to a self-defeating philosophical relativism that has, in turn, weakened the stature and substance of Hinduism to its very core. The doctrine of Radical Universalism has made Hindu philosophy look infantile in the eyes of non-Hindus, has led to a collective state of self-revulsion, confusion and shame in the minds of too many Hindu youth, and has opened the Hindu community to be preyed upon much more easily by the zealous missionaries of other religions. The problem of Radical Universalism is arguably the most important issue facing the global Hindu community today. In the following, we will perform an in-depth examination of the intrinsic fallacies contained in this inherently non-Hindu idea, as well as the untold damage that Radical Universalism has wrought in modern Hinduism."

"The Mountain Metaphor
"Truth (or God or Brahman) lies at the summit of a very high mountain. There are many diverse paths to reach the top of the mountain, and thus attain the one supreme goal. Some paths are shorter, some longer. The path itself, however, is unimportant. The only truly important thing is that seekers all reach the top of the mountain."

While this simplistic metaphor might seem compelling at a cursory glance, it leaves out a very important elemental supposition: it makes the unfounded assumption that everyone wants to get to the top of the same mountain! As we will soon see, not every religion shares the same goal, the same conception of the Absolute (indeed, even the belief that there is an Absolute), or the same means to their respective goals. Rather, there are many different philosophical "mountains", each with their own very unique claim to be the supreme goal of all human spiritual striving. As I will show, Radical Universalism is not only an idea that is riddled with self-contradictory implications, but it is a doctrine that never originated from traditional Hinduism at all."

"A Tradition of Tolerance, Not Capitulation
Historically, pre-colonial classical Hinduism never taught that all religions are the same. This is not to say, however, that Hinduism has not believed in tolerance or freedom of religious thought and expression. It has very clearly always been a religion that has taught tolerance of other valid religious traditions. However, the assertion that a) we should have tolerance for the beliefs of other religions, is a radically different claim from the overreaching declaration that b) all religions are the same. And this confusion between two thoroughly separate assertions may be one reason why so many modern Hindus believe that Hindu tolerance is synonymous with Radical Universalism. To maintain a healthy tolerance of another person’s religion does not mean that we have to then adopt that person’s religion!"