Once upon a time, boys were boys, girls were girls, and binary was a mathematical term.
Today, however, the idea that there are only two sexes, male or female, which you stay in from birth, has been condemned as transphobic. The sex binary, we are told, is just an idea. To argue otherwise is sometimes regarded as hate speech.
This new orthodoxy is a denial of reality, a rejection of science, and an attack on God our Creator.