I don't see how it is a contradiction. Sure, it could be a contradiction is the common monotheist sense, but monotheism is not the only definition of the divine. I can point to Hinduism as an example which has a completely different definition of "god" means. I believe the sociological definition of a cult is a religious movement in which has novel religious beliefs, with a high degree of tension with the surrounding society. However, that's not how the term is used. As well, the traditional use of the term "cult" in Christianity, from what I'm reading in Wikipedia, is one that is akin to heresy; in such a context, it's not really an appropriate term to use today given the pejorative use of cult. Such would be an equivocation fallacy; Roman Catholicism and Mormonism are accused of cults in this sense, taking advantage of the other definition of the word cult. Same with Shi'a Islam. Cult is a loaded term, which is why sociologicalists use NRMs (New Religious Movements) instead. This isn't really political correctness; cult has become a word that has no well defined meaning and is associated with something that is inherintly bad. The fact that there can be well-defined meanings of cult is irrelevant, as a word gets its meaning in how it is used.