The author, and the authors he quotes are horribly intellectually dishonest.
Something does not just come into existence ONLY because some academic, intellectual, writer or even the law gives it a name - like “heterosexual”. Being “heterosexual” with or without it being named, as such, was “the norm” without question, as far back as humans have been around, and the fact that there were always exceptions misses that they were exceptions, exceptions to what, to what was “the norm” - the majority case, the most frequent case, the case most people expressed. Merely naming it had nothing to do with it.
It’s just illogical word-spew. Don’t try to make sense of it.