Christian Concern has defended a video released in response to the launch of the Church of England's Living in Love and Faith (LLF) resources.
In it, John challenges aspects of the LLF video, including the decision to open with a transgender vicar, and the presentation of marriage by a heterosexual couple as "just a deep sense of commitment".
The video triggered a backlash from LGBT activists who have called it transphobic, homophobic and "abusive". They have also claimed that it undermines the LLF process, which is intended to draw Anglicans with opposing views on sexuality together in dialogue.
In a statement, Christian Concern CEO Andrea Williams - who is also a member of the Church of England's General Synod - denied that the video was abusive.
"There is nothing abusive about the video we released relating to Living in Love and Faith. It does not contain personal attacks and simply calls on the Church of England to uphold its Biblical understanding of sex and gender," she said.
"It is, in fact, the revisionists in the Church who have resorted to personal attacks by comparing conservatives to rapists and Holocaust deniers, by making false reports and by using very coarse language in public.
"They have reacted this way to everything made by those upholding Biblical teaching, no matter how gently it is put. They were never interested in engaging in genuine Biblical reflection, only in getting their way."