Before I begin, I do have friends that identify as homosexual, bisexual, heterosexual, and transgender. They all know how I feel about this issue and understand. The majority happens to agree, which I think is interesting and fantastic.
In today's society, it seems that everyone needs their own title to feel special and significant. They don't want to be caught in a loop that isn't "theirs" or be associated with something that they are, in fact, definitely associated with. Sexual identities, sexualities, and genders are a GIGANTIC factor with this issue because people are finding more obscure ways to explain things so they are able to feel like an individual.
Back in the less complicated days, there were homosexual, bisexual, and heterosexual people; plain and simple. One was attracted to the same sex, one was attracted to both men and women, and the other was attracted to the opposite sex. But now, there's all these different sexual categories that are honestly unnecessary and just cause meaningless confusion. Confusion arises when most sexualities are literally the same thing, but people don't want to see it that way. Examples? Bisexuality and Pansexuality.
By definition, bisexuality is the romantic, sexual, and emotional attraction/sexual behavior toward both males and females, or romantic and sexual attraction to people of any sex or gender identity; the latter aspect is sometimes alternatively termed pansexuality.
By definition, pansexuality (or omnisexuality--i.e. also the same thing by the way) is the sexual, romantic, and emotional attraction towards people regardless of their sex or gender identity. Pansexual people may refer to themselves as gender-blind, including people that are outside the gender binary; a branch of bisexuality.
Both have attraction to any sex or gender identity; men, women, transgender. Literally the only difference is that pansexual people can be attracted to non-binary people, which still are biological men and women, and/or recognize more than two genders. But after all, THERE ARE ONLY TWO GENDERS.
Yes, trans people have their own title and I won't argue that. But where this is concerned, they are transitioning from one biological sex to the other.
Bisexuality is the overall term. Pansexuality is an unnecessary branch of bisexuality. They are the same thing.