This is the problem. There's no difference to people. Arguing any nuanced part of the conversation is often met with exaggerated reactions of "you're anti-trans" or "you're dismissing transexualism as a whole", which is not the case.
So yes, the pro-trans movement on many online spaces is very ideological - they even claim it themselves (transmedicalism vs. gender identity, etc). Very little of it these days is based on science or medical prognosis.
I do understand as well your reticence around the ideological space that a lot of online spaces take place in. To that I’d just say that this stuff is fairly new, and you have a lot of young people finding and differentiating their identities as they’re going through quite a process.
My opinion is frankly it’s a wonderful thing, to have it so people can prioritize their emotional well being enough to not have their natural individual differentiations beat out of them as so many cultures have done. In doing so, discovering how much of a thing gender dysphoria is for some, and allowing them to lead much much better lives.
If we're talking about someone who transitions in their teens and has no other options for sport in their adolescence, I would agree that's a much more difficult and ambiguous situation.
That said, I don't really agree with this clarification either: no trans woman is setting out to have gender reassignment to bully their way into competing against women who were lifting since they were teenagers. I think you are attributing this to malice that is simply not there, and it is only an artifact of unfortunate circumstance. Trans women certainly don't want to be in this situation either: I'm sure they would much rather be born biologically female and compete that way!