It was a question about categories. Are there two categories of gender / sex? The answer is no. These people exist. They have entire lives which are as meaningful as any other. Why wouldn't they matter?
When it comes to policymaking, any prudent work requires the analysis of how many people would be impacted. It's not enough to just say "well there's like 100 people in a population of 300M we should change everything just for them".
The OP asked what evidence exists that gender and sex are non-binary. It's in reference to the words someone said in the article, not hypothetical policymaking.
