Are you also keen not to "negate" millions of women globally "out of existence"? Like the women of Afghanistan? Because if using a word to describe someone with which they personally would disagree "negates them out of existence", then that's the very effect that your redefinition of woman to an internal state as opposed to an objective reality is having on all those women who don't share your belief in gender identity or are not even aware of the concept.
Again, as with my post above on single sex spaces above, do you see that we can't have it both ways? Someone, somewhere, loses out.
So, again, as with my post on single sex spaces above, this leads me to consider other factors in drawing my conclusions about the word "woman" (or "lesbian", for that matter): namely, where the greater need lies.
In utilitarian, numerical terms, that's easy, obviously. But the other factor I consider is that transwomen already have a descriptor to distinguish themselves legally, polically and socially - "transwoman". Whereas, if they take the noun "woman", too, women have nothing to distinguish themselves. Indeed, to take your emotive phrase above, many millions are "negated out of existence".
So, once more, as with my post on single sex spaces above, this leads me to the clear conclusion that adult human females globally have the right - an urgent need - to a distinct signifier: "woman".