One would never expect the whole populace of any group of people to be on board with an idea or philosophy. Especially, as you say, one as diverse as the Transgender population. However, there is every reason to wonder why more aren't interested in it which was what the questions in the article are driving at. The same could absolutely be said of the deaf community and anyone else who would stand to benefit from Transhumanist approaches to technology and social systems. The more the merrier and hopefully more successful so if a wider array of people can be reached it would be great. Transgender individuals do stand out a little in this regard though and make them especially interesting in terms of wondering why they are not as involved. The most notable simply being the scale to which many are interested in modification and customization. A group like the deaf or blind want one fairly specific feature repaired. A very important one to be sure but they are less likely to want to change so dramatically.
I wholeheartedly agree that I and anyone else I can convince to help should be reaching out as much as possible. In some ways this post was a step in that direction. To whatever extent possible it might be worth coordinating on some elements. After all the fundamental interest is similar - changes and improvements to the body. It will be a challenge to connect with the community but an interesting challenge to be sure and well worth the effort.
I will reach out to KittyHPlus and see what may be of interest.
RE: There should be more 'Trans' in Transhumanism