The acronym has become unwieldy. I believe some of the identities after "T" share struggles with the preceding letters, but many others are simply there for recognition. Intersexed people can go through some real shit in life because of how they are perceived and treated by society, though I am at a loss to see how an advocacy group addresses the struggles of asexuals or demisexuals. I am unaware of how people who have no sexual attraction to limited sexual attraction towards others experience discrimination and violence in society.
The original three and then four identities existed to unify a community for political reasons, so they can act together to enact change on local, state and national levels. From those letters, advocacy groups arose to address the needs of the "community" as a whole, and specific identities. And these needs were along the lines of housing, jobs, access to social and public commons - and most importantly all things pertaining to rights unrecognized by the state.
I think people forget that.