True about the way they say it but then again, that is just one ending and not even the flawless one.

They are also presented as a boy in the Japanese website description and the glossary is neutral unlike the English one so no wonder the Japanese audience is interpreting them like that.

Instead of going out of your way to "correct" people's interpretations of the character you should just ignore it, move on and let people be happy. Don't be mean please.

You can add your own interpretation or any nuances you've noticed regarding a person's point of view but stop trying to start shit with "well you are wrong because x and y", otherwise you are no that different than people saying shit like this:

"Even if Bridget was a girl they would be a cis girl by definition because they were assigned female at birth so there is no way Bridget is ever going to be trans, unless they were a trans boy, but then you have to take the L and admit they are a boy. Bridget isn't and will never ever be a trans girl. Cope."

Bridget is a girl. That's what you want and that's a fact. The fact that Bridget can also be a GNC boy or even non binary or agender depending on the interpretation of other people shouldn't make you want to tear them down, unless you are just outright evil and are happier taking away other people's representation than getting your own.