Too many posts to answer, but perhaps I can get through a few points:
Most of your arguments are based on the notion that sex is a simple binary purely defined by gametes. It isn't - they are just one of thousands of sex characteristics. Having said that, some of you seem to prioritise gonads rather than gametes whilst others prioritise chromosomes. But that's the point, there are many sex characteristics and the particular ones we use when trying to fit a person into the artificial binary that our culture has constructed vary. You use the above, I prioritise gender identity above all of those.
Changing rooms: eek, I can't imagine why anyone would want to change or shower in a public space, particularly if it's a place where people are just openly wandering around full-frontal naked. If you do that, you're going to see genitals, and as some women have penises, that's going to potentially include a penis on occasion. Your choice.
Did someone imply I'm a rapist? Well, I posted that no trans woman should feel obliged to say she is trans before having intimate relations. Shortly after that the following appeared on the Bunbury thread:
"It is very, very creepy though - to take such obvious delight in outing yourself as a would-be rapist on the feminist section of a very female dominated forum. This is definitely someone who gets off on boundary violations, at the very least in the virtual world. I couldn't possibly speculate about the real world, but let's just say if certain behaviour patterns visible on here carried over, I would not be in the least surprise."
But hey, maybe it's just a coincidence and they were talking about someone else.
"Born in the wrong body"? It's a metaphor - always has been. I use it on occasion myself just as way of telling someone what being trans feels like. It's not literal. People are moving away from it because non trans people (we need a word for that) seem to have difficulty understanding that it's a metaphor.
Referring to infertile women when talking about trans women is only offensive if you think that there is something horrible about being a trans woman.
DSDs are relatively uncommon differences of sexual development. So is being trans, hence the reason both often appear in the same conversation. See previous posts about issues like the pelvic structure of trans men being masculine or genetic issues in trans people like these:
www.abstractsonline.com/pp8/#!/4592/presentation/578abstract
pubmed.ncbi.nlm.nih.gov/22810992/
Can a human change sex? Well, I consider trans girls to be female, so they don't have to. Having said that, many of the thousands of sex characteristics are highly mutable, especially if you take cross-sex hormones at puberty, so there's that.
So transition isn't what you think it is - it isn't a change of sex, except in a legal and social sense - physically, it's just a matter of changing physical characteristics that cause you distress. As I said before, it's the same as a non-trans woman having excessive facial hair removed or a non-trans man having breasts removed. Humans are social animals - we don't like to look completely different to the people we identify with - it's the same for trans and non-trans alike.
"Trans race" and "trans age" are red herrings. Your race is defined by your ancestry, your age by chronology, but sex is much more complex and can be defined in various ways from gametes to gender identity and can vary by context. People here have a very narrow definition, people like me, and indeed most biologists acknowledge that it's way more complexed and nuanced.
Hope that helps.