A single world religion stemming from and catering for this religious instinct would make sense and I could accept in, but the concept is surely voided by such a diversity of creeds.

The answer lies in a little understood fact. Religions do not exist to serve any particular God or gods; they come into existence for the benefit of humans. Were the purpose of religious expression simply to serve God, then a single religion would indeed suffice. However, when it has to serve the spiritual needs of diverse races and cultures and of human individuals in various stages of development, then obviously and logically a diversity of outward forms and interpretations is required to satisfy such a wide range of needs. The misconceptions concerning worship and glorification arose when mankind regarded God as some kind of super-ruler and therefore enlarged on what was considered kingly requirements, one of which was adulation by the subjects. The divergence of religious beliefs arises in interpretations and conceptions. The latter are not important in the theological field, except to small minds which cannot grasp the higher concepts of The Supreme Being.