Complex sentence: The concept of pansexuality deliberately rejects the gender binary, the "notion of two genders and indeed of specific sexual orientations", as pansexual people are open to relationships with people who do not identify as strictly men or women.
Split into simpler sentences: The concept of pansexuality deliberately rejects the gender binary, they reject notion that only two genders exist. As pansexuals are open to relationships with people who do not identify as strictly men or women.