The law requires tampons in the bathroom of anybody who could identify as a female.
IOW, every bathroom.
That’s what the article said.
What the article says (and it’s surprising that you used NPR as a news source since it’s usually regarded as fake news here), is meaningless, but the article does not say the law requires tampons in the bathroom of anybody who identifies as a female. Nor does the law, which states that “menstrual products must be available to all menstruating students in restrooms regularly used by students in grades 4-12”. Nowhere in the law is there any mention of students who identify as female, or even boys. The law states that a plan for enactment of the law will be determined by the school district. Nowhere is there a requirement that all bathrooms have menstrual products, not even all girls bathrooms.