While that is the case, the fact laws change is in large part because there's lawyers who are willing to play fast and loose with technicalities. The fact that we're seeing rape cases by transwomen in England and Wales get thrown out of court because the victim refused to use "she" pronouns for their attacker means that we're closer and closer to some asshole lawyer deciding to test that loophole by waiting until the victim referred to their attacker as "she" and then saying "she called my client she! She admits my client is a woman! That means that this is merely sexual assault, and since you didn't charge her with sexual assault and only charged her with rape, you have to throw the whole case out!"- and it's likelier and likelier that would WORK right now.

So, better to formally close it up and say "don't even think about it. They have a penis, even a feminine penis, they raped them"- and while you're at it close up a bunch of other backwards parts of the law as well.