To answer this, look at what happens if you are caught reading material that dissects the religion. Suppose you are caught looking at objective reviews of the religion. If it comes from the news, they will bash the news as Satanic (but, if there is something favorable about the religion, they will praise God for moving the media). If it is coming from someone that is, or was, in it, you can be disfellowshipped. That would red-flag the group as a cult.
Additionally, how many people's lives have been ruined by the religion? Now, what happens if they want no more and try to leave? They are cut off from the congregation, even family, and that is another major red flag issue. With the high number of people's lives ruined, I would definitely say that it is a cult--and a whopper of a waste of time.