Not to interfere but who is surprised to hear Fr Ad Hominem Naturalis citing another Fr Ad Hominem to back up an ad hominem attack? Anybody can call another person's religion a cult. If we were to list the labels people have for each other we'll take all the bandwidth. If it matters, have you read any book on the world's biggest cult? Labels do not carry scriptural weight.
Cult
In the sociological classifications of religious movements, a cult is a religious or social group with socially deviant or novel beliefs and practices.[1] However, whether any particular group's beliefs and practices are sufficiently deviant or novel is often unclear, thus making a precise definition problematic.[2][3] In the English speaking world, the word often carries derogatory connotations.[4][5]
The word "cult" has always been controversial because it is (in a pejorative sense) considered a subjective term,
used as an ad hominem attack against groups with differing doctrines or practices, which lacks a clear or consistent definition.[6][7]
http://voice-wilderness.org/questions-about-god/is-roman-catholisim-a-cult/If the mother is a cult then naturally all her daughters who remain faithful to her unscriptural teachings is equally cultic.