I don't reject their experiences. I reject their claim that these experiences are womanhood because to do so means rejecting my own experiences. They know what it is to be them but they do not know what it is to be me.
The overreach is not when they say "I feel like this", it is when they say "I feel like you"
Because you need to realise that Women defined as adult human females are not saying "we are women because we feel like each other" - how would we know that any more than a trans identifying man does? - we are saying "we are women because we have the same physical sex", an ojective fact which is known at birth for almost all of us and does not require us to make any assumptions about anyone's inner life.
Yes there are a very small number of people, like well below 1%, where it may not be clear immediately or may even be initially wrongly observed, but those exceptional experiences do not invalidate the experiences of the 99.lots% of people whose sex is known by both themselves and others from the day they were born, and for whom the way their body exists, the way they see themselves and the way people treat them because of it, and how these threads entwine and intersect with each other and their other life experiences form part of the formative story of their lives. Our sex is a fact and it is material in our lives physically and socially. We need to name it and we need to be able to name the people who share it with us.
Do you see? This is not about which is "valid", it is about two experiences which cannot be the same thing because they are mutually exclusive trying to claim the same name and space.
A "woman" cannot both be "a state that does not require having a female body" and "the state of having a female body", because those definitions are mutually exclusive. They are separate concepts and they need separate names.
And given that they undeniably are separate concepts and so need separate names, I believe the only moral choice is that woman continues to mean adult human female because that was the original meaning of the word, that group of people still exists, and there are legal rights and cultural and social histories and experiences that belong to those people wriiten under that name which have no connection to trans-identifying men.
The trans identifiying men and the women who feel kinship with them are the new group. They have every right to exist but they need to find their own name and their own identity.
This is not a case of who is "valid", this is just a case of logic and fairness.