In the same way that Christianity or Wicca are real

it's also real that there are people who don't believe than one can be non-binary

So if someone holds the view that they don't believe it's possible for a person to be a Christian even though there's millions of people that call themselves Christian do you think that means the question of whether or not there are people that are Christian is up for debate? That's insane.

The debate isn't about this.

You're right. It's about whether nonbinary people and trans people in general deserve rights and social validation. Which they do. End of discussion.