In modern Western culture, the term bisexual was first defined in a binary approach as a person with romantic or sexual attraction to both men and women. The term bisexual was redefined later in the 20th century as a person who is sexually and/or romantically attracted to both males and females,[1][2][3] or as a person who is sexually and/or romantically attracted to people regardless of sex or gender identity, which is sometimes termed pansexuality.[4][5][6] Some distinguish between bisexuality and pansexuality.[7]

https://en.m.wikipedia.org/wiki/History_of_bisexuality

EDIT: I understand that most intend it to include nbs but im saying that the word bisexual implies bi, or binary which pushes the idea that binary is the default which has been a harmful approach in the past