[how's this for irony]

You can not confirm whether a belief system is actually a cult using your common sense. If common sense was enough to recognize a cult or false religion, nobody would ever be involved in one! Further, you can not expect a cult to admit they are one. Otherwise, why would anyone remain a member, or be interested in joining? Remember, cults will always have some sort of support for their beliefs, and the people involved sincerely believe what they are doing is right.