Oi vey! Let's just clear up this whole "What is a cult" question already. Mark Oppenheimer could have saved us all the trouble, but research is obviously not one of his strong points.

The definition of the word "cult" is not subjective. It's a real word that had a precise meaning. The definition of Cult has nothing to do with denying Christianity or being non-Christian (the word predates Christianity). The following is the definition of the word "cult" from the American Heritage Dictionary:

Noun: 1a. A religion or religious sect generally considered to be extremist or false, with its followers often living in an unconventional manner under the guidance of an authoritarian, charismatic leader. b. The followers of such a religion or sect. 2. A system or community of religious worship and ritual. 3. The formal means of expressing religious reverence; religious ceremony and ritual. 4. A usually nonscientific method or regimen claimed by its originator to have exclusive or exceptional power in curing a particular disease. 5a. Obsessive, especially faddish, devotion to or veneration for a person, principle, or thing. b. The object of such devotion. 6. An exclusive group of persons sharing an esoteric, usually artistic or intellectual interest.

Etymology: Latin cultus, worship, from past participle of colere, to cultivate.

I hope this sheds a little bit of light on this discussion. And, incidentally, Scientology fits the definition precisely.