As I've been saying, LGBT shares a common history, including how we were all lumped together as queers. And the increased/mass inclusion has made it so the T is being pushed out by people who previously never even attached themselves to LGBT or were considered queer and don't have enough in common that we can relate with them. It's including those who do not share our history. It's including those who didn't have anything to do with us in past decades when prejudice against queers was far more widespread and severe than it is today, and even being gay was an accusation.
Do you believe ace people didn't exist (and weren't accused of being gay: "why haven't you settled down with anyone, Thomas?")? Or trans people that wouldn't/couldn't transition?
I'll agree that the lived experience is different, but I'm not sure I agree that the "history" is different; and I'm not sure that even if it were, that's grounds for exclusion.
This is all especially the case when if you really want to concentrate on just trans issues that meet your particular criteria, you can do that without excluding people from the wider community.