It feels inappropriate to you because she is high profile and you know she had a male identity. Trust me, you wouldn't even know someone was a transwoman from appearances in many cases. Most of them sincerely wanted to transition to a female identity. The problem is the male and female bifurcations in sports had always to do with physical strength and not the social construct of gender (aka looking like a woman).
Of course in many cases I would not be able to realize that a person who looks like a woman is not a real woman.
But that is not the point.
The point is that men and women are genetically quite different. And the fact that about 0.01 of the population is intersexual doesn't change that.
Today we have the medical knowledge to help a man who want to look and live like a woman (and vice versa). I appreciate this. These trans people should not be insulted, made fun of, discriminated when looking for a job etc.. Of course not.
But competing as a former man in women's sport? After a transition which took place after the start of male puberty?
I can't get my head around it how someone might agree with that. What is wrong with our Western culture? Where did we take the wrong turn?
BTW, people who help a young kid pre-puberty to transition should go to jail. The kid's "consent" to such a procedure notwithstanding. It is the same as the US concept of statutory rape. There the consent of the youngster doesn't absolve the adult from the crime either.