I am reading currently the Rivka Nir's book.
He denies the existence of followers of John the Baptist:
...I tackled the prevailing view in research that the Fourth Gospel's description of John is attributable to an alleged polemic between the Christian congregation and John's disciples, members of a Baptist sect, who claimed John rather than Jesus as their messiah. I analyzed the evidence sustaining this position and attempted to prove that it does not imply the existence of such a group and its polemic with the Christian congregation in first century CE. My conclusion is that the explanation for the Fourth Gospel's assertions that deny to John any messianic title lies at the theological an not the historical level. It is precisely John's eminent status in this Gospel that created the need to distinguish between him and Jesus.
(
The First Christian Believer, p. 264, my bold)
The implication is that the
Baptist Passage was interpolated necessarily by Jewish-Christians, since there were no followers of the Baptist interested to confute Christian claims by using interpolations in Josephus.
What derived my attention is this quote:
To my mind, however, the various aspects distinguishing John's death nearly fit Christian martyrdom. As I have attempted to show, the principle of faith for which John was willing to lay down his life is the prohibition against divorce and remarriage, which was among the core values of Christian theology.
(
ibid., p. 237)
I note a contradiction between this John and the Jesus bringing a sword and not peace, i.e. the Marcionite Jesus who breaks any link with the material world of the Creator.
The divorce is a marcionite motive: the Marcionite Christian has to divorce himself with this world. Jesus divorces from his family, inducing the latter to consider him mad.
So this anti-divorce John fits perfectly an anti-marcionite icon.