DISCLAIMER: The following post is solely my opinion, so Bible-thumpers who wish to refute it may nonetheless do so, but unwarranted insults or bashing because of my comments is unnecessary.
Of course if you ask someone who is a member of a Christian denomination, for example Roman Catholic, if they are a member of a cult, they would say NO. This is no different than asking a Jehovah's Witness if they are in a cult, they will say no. When people are involved in a cult they are so indoctrinated they will deny it under all conditions.
However, when you look at it from an outside, unbiased perspective and study the doctrines of many Christian (Catholicism, Protestant, Jehovah's Witness) and many non-Christian (Islam) religions, you will notice that they exhibit cult-like behavior. They have rules specific to their religion which dictates the very lives of it's members (CONTROL). They preach the "we are right, everyone else is wrong, we have the only true understanding of God and all others are condemned to death) (FEAR)
In my own honest opinion, in their own way, all religions are cults. They want your money and your life, and spew their own interpretation (propaganda) to convince you that they alone are correct and understand the very nature of God and the purpose of life.
More atrocities have been committed in the name of God and religion than for any reason. Shall I cite examples? The Holy Crusades, the Palestinian uprising (intifadeh), the Inquisitions, World Wars in which chaplains and priest on both sides preach to the soldiers that the same Christian God is with them? Islam radicals and 9/11?
Religion is the single worst thing that has been perpetrated on mankind in history in my own opinion. Then again I am an atheist/agnostic, I expect to be lambasted.