This is what I gathered happened, there won't be a test. Bisexuality as a sexual behaviour label originated as a 19th century medical term, and it was adopted by the community eventually. When the issue was brought up of it being a binary word for a not-necessarily binary attraction, there were two major solutions. One was to keep using the word and change the meaning, which has the benefit of keeping the label (imagine if there was a problem with eg the word 'gay' and gay people might feel if facing changing their label) and it was a known term. Using a different label was the other solution, and it has cleaner etymological support and it puts a rejection of binaryism in the label itself. Also it is explicit about it being about more than two, whereas there is a percentage of bisexuals who it is about just two.
In etymological news of mostly-false equivalence, I was surprised to find so few lesbians have any association with the Greek island of Lesbos, and I once saw a supposed gay person momentarily lapse into sadness.
Also I find it amusing when people understand pansexuality as an attraction to all things rather than all genders because I imagine what other sexualities are if they are read in the same way. Homosexuals are all attracted to the same thing, heterosexuals to other things...