So you are saying that if someone preaches something as truth that ain’t truth then they are a cult? For instance, if they preach that a person who is being sanctified will speak in tongues, then they are a cult?
Yeah. So take the Catholics, they teach they need the church to help them get to heaven. That teaching binds them to the Catholic Church.
There are different levels of errors, some of which rise to heresy. The (Catholic) one that you mentioned is heresy, meaning that it will be damnable for the soul. Teaching somebody that the Bible says that they must speak in tongues to reach the next level sanctification, or if they’re a woman they should only wear dresses, that babys should be baptized to be brought into the church, is error, maybe even gross error, but it’s not going to lead a soul to hell. The same can’t be said of the Catholic doctrine that you just mentioned. The Catholics are a theological cult for that very reason. You’re wrongly conflating categories and making up your own definitions.