I consider Buddhism to be the most profound expression of human religious sentiment [although I'm a bit biased ;D]. I don't find this thought alienating, and I don't think that "religion," "philosophy," and "Dhamma" are mutually exclusive terms. I look at that sutta quoted by Dukkhanirodha as discouraging spiritual beliefs which are clung to as ultimate truth without any sort of personal verification a la Vibhajjavada. Think about what the term "creed" means. People often equate it with the word "religion," but the word itself points to a specific core set of religious beliefs which are clung to as ultimate truth, even whenever experience suggests something else. In some religions, the creed is effectively the religion and the acceptance of the creed is taken as the entry in to spiritual life. I think of the shahadah, the obligatory statement of belief for all Muslims which serves as the basis for the key points of Islam ("There is no God but Allah [the characteristic strict monotheism of Islam] and Muhammad is his Messenger [which lends divine authority to the Qur'an and all other Muslim beliefs which emerge from that book.]) This statement is also the means of officially converting to Islam. Of course the Buddha would oppose beliefs of a creedal nature, because creeds are based upon speculation and lead to a great deal of clinging to ultimately useless views. Creedal religions lay out religious paths which are founded upon unverifiable claims and while these claims are taken as the basis of spiritual life, liberating discernment cannot occur. I think you can see this point of mine in the sutta itself:
""Outside here the followers of creeds, place their confidence in views." They place confidence in views instead of experiential discernment.
Here is how I think of the word "religion" [which, admittedly, doesn't count for much]: Any institution with a prescribed set of beliefs and practices which are used to "attain," "realize" or "connect to" something beyond the range of "conventional experience." I put these phrases in quotation marks because they obviously aren't sufficient to describe Nibbana.
I do not want my house to be walled in on sides and my windows to be stuffed. I want the cultures of all the lands to be blown about my house as freely as possible. But I refuse to be blown off my feet by any.- Gandhi
With persistence aroused for the highest goal's attainment, with mind unsmeared, not lazy in action, firm in effort, with steadfastness & strength arisen, wander alone like a rhinoceros.
Not neglecting seclusion, absorption, constantly living the Dhamma in line with the Dhamma, comprehending the danger in states of becoming, wander alone like a rhinoceros.- Snp. 1.3