A cult is any group of people who have a total devotion to their leader.
Any Pastor who encourages you to cut off contact with Christians outside of their Church has the earmarks of a cult.
If a Church leader encourages its members to avoid what other Churches are doing, including concerts, vacation Bible schools, youth groups, and ministries that serve others, they are leaning toward cult-like behavior.
Religious communities thrive on connection and openness, but sometimes, leadership can foster concerning patterns. True spiritual communities encourage growth through diverse relationships and experiences.
Some people are believers in Jesus, but they make the way of Jesus look more like a cult than a community. They push isolation and exclusivity on their people. They seem to be more interested in control than connection. They are not a cult, but they are certainly cult-ish.
Not everything that wears the name of Jesus is from God.