Dharma: religion, science, philosophy or humanism? - the question is often put in West of the placeof the education of the Buddha, the Dharma, among the big spiritualities of the humanity.
As often expresses him the Dalai Lama, the education of the Buddha recovers what is usually heard(understood) by religion, philosophy, science of the spirit or humanism.
So, if the term religion indicates(appoints) a shape of faith in a creator or arguments of authority whatever they are, Dharma is not a religion. On the other hand, if we hear(understand) religion in its etymological sense(direction), as what connects horizontally the men(people) between them and their ancestors, and vertically what connects them with the timeless principle or with the transcendante and immanent nature, then Dharma is a separate religion out being reducible in one of these categories.
It is a philosophy if we hear(understand) this term to the original sense(direction) of love of the wisdom which gave him, Pythagore. And as a philosophy, he suggests understanding(including) basic nature of the reality, the reality in an experimental approach. The old Socratic proverb " Know yourself ", in other words: " know what kill are and you will know the gods and the universe " is a profoundly Buddhist spirit.
Buddhism considers the ecosystem of the life: the interdependence between human being and Nature in this point of view, it has a profoundly ecological dimension.
Finally, Dharma considers the human experience in its global, holistic reality. It is from this point of view a fundamental humanism.
I think that to see the Buddhism only as a philosophy of life - what is effectively already rather interesting, it is to see it in its most simplistic shape and simplified.
Buddhism teaches the respect for the Nature and the not violence among the men(people). Religion or philosophy, what that changes? There are religions in the world much worse.
A very interesting question! Have a good night.