Bisexuals face some stereotyping and exclusion from both sides (lesbians/gay men and straights).

While "bisexual" may be a temporary state or label for some people exploring their sexuality, for others, it is a lasting identity.

I question saying "Everyone is bisexual" or "Nobody is bisexual". Both deny some people's experience and make "bisexual" a meaningless distinction.

Being a bisexual doesn't imply one has two sexual relationships at once. (Monogamy & non-monogamy are a distinct question.)

Being bisexual doesn't imply one is (or can choose to be) sexually attracted to everyone. Erotic feeling is idiosyncratic, with urges as diverse as desires for "tall brunettes" or for "non-smoking politically-active vegetarians".

Being unconventional does not mean one has no morality, values or standards.

An integrated bisexual identity can have qualities beyond a simplistic "half and half" mix of gay and straight sensibility.

I can't accept an ethic that accepts exclusive heterosexuals or homosexuals because they "were made that way", but condemns bisexuals for making the "wrong choice". To me this "choice" is like asking "would you like to cut off your left hand or your right hand?".