I've read similar comments on this episode from time to time. It never really struck me that way, but I guess you do have to accept the bond between Kira and Ghemor for this story to work. It's always worked for me because I felt it was strong enough in Second Skin to be believable here as well, or for this to be believable as an extension of that.
It seemed to me like they had to have corresponded in SOME way that we never saw--but, I also thought that they bonded very strongly as a result of their shared experience in "Second Skin." I also always imagined a lot happened off-camera during the ride back to DS9 from Cardassia, and back on the station before Tekeny went into exile with the Mathenites.