A number of destructive cults have developed from and even within mainstream religions.
This is correct. For example, in the Catholic Church, there are several powerful cults within it: Opus Dei, Regnum Christi (Legion of Christ), Communion & Liberation, Focolare and Neocatechumenate. Within Judiaism, several ultra-orthadox sects, settler groups and Jews for Jesus are cultic. Within Islam, there are groups like al-Qaeda and the Nation of Islam. Within Hinduism, there is the BJP and Hare Krishnas.
Cults are a universal part of the human experience; no religion is immune.