There may be a mindset that because this forum is transgender based, you need to stick to topics of that nature. I belong to forums for guitar, and ham radio, and they're the same way - forum members mainly talk about ham radio or guitar related topics. One fix that those forums use to facilitate the member discussions to about things other than what is the forum's main focus is, is to set up off-topic/general discussion sub-forums (Bag Dog Cafe for instance on the TDPRI [a forum for Telecaster guitar players]), where people can chat about anything (as long as it isn't offensive in nature).
QRZ.com (one of the largest ham radio forums in the world) even has a sub-forum where you can talk about politics (frankly it can get kind of nasty on that sub-forum - it's almost impossible IMO to change the mind of a "true believer" when it comes to political topics, and trying to do so can cause a lot of tension). Maybe Susan's needs a sub forum for off-topic discussion.
Other factors that determine whether or not off-topic discussion occurs, are what your comfort zone is, and how well you know the person. I became good friends with another post-op who lives in California, back in 2003, while we were both recovering from our Suporn SRSes in Thailand. We still chat on the phone weekly, and I just talked to her last night on the phone. While we talk about topics that relate to us as post-ops, the vast majority of our chats have been about anything but topics of that nature. Last night it was about politics, ham radio, electronics (we both have ham radio licenses [I've been licensed since I was a teenager in 1978], and my friend also used to be an electronics tech.), and even a wee bit on the nature of religion and god. Other times its been about current events, pop culture, music (she's into more of the garage band stuff, while despite going on 56, and becoming far more eclectic musically [jazz, country rock, acoustic guitar music, even good symphonic music - after all I played symphonic music through my Sophomore year of college], I'm still a bit of a metalhead [I'm one of the original thrash metal kids and even played lead guitar in heavy rock bands]).