Unconsciously, they are always tied to the "nazarene" thoughtform (even if this is rather death, I believe). Consciously, they can have some values, so having a conscious relationship may be helpful to stay grounded in the "outer world" outside JoS. Otherwise you won't talk to barely anyone except here.
Building deeper relationships that involve chakra connections, energy exchanges, etc. may result in polluting your energies and raising your need of cleaning both chakras and aura. Those people will always act as proud of their xianity.
Would you like to be invited at their home and eat lunch under their cross hanged to the wall ?
I am a bit extreme on here but I tend to cut off outsiders, in case relationship gets too deep. This can be fault of some weakness in myself, also I do not want to waste time.
If they do not study the JoS (deep, and repeatedly for deprogramming), their unconscious mind will always be tied to xianity and, first or late, this may come to the surface.