Whilst there is a considerable stigma surrounding bisexuality, I do not believe that bisexuals make up the majority. Heterosexuality is the most common. Someone once said to me "gay men are disliked because they like men, lesbians are disliked because they don't", and now and then I think about that statement. Anecdotally, I am a part of an LGBT forum and have been for a few years. I've noticed this is often the case when comparing "I think I might be gay" type posts from female users to male members.
A common misconception regarding human sexuality is that all women are bisexual, and men are either straight or gay.
I once had a friend whom was bisexual, but he identified as straight despite saying that he is sexually attracted to both men and women. His reasoning was that he had more interest in women and felt like he didn't fit in the LGBT community as a result. Unfortunately, in some corners of the community there is a considerable amount of biphobia. Some individuals use the term "bi-het" (bisexual heterosexual) to shame bisexual members of the community who happen to prefer the opposite sex. They do so because they believe that such individuals get what they refer to as "straight privilege" and aren't oppressed enough to be a part of the community.
Which is just ridiculous. The term bisexual heterosexual is silly as well, you can't be heterosexual and bisexual at the same time by definition.
Perhaps it should be noted that there does seem to be a disproportionate amount of women identifying as "predominately heterosexual, but more than incidentally homosexual" (or a Kinsey 2, if you prefer) whereas men that refer to themselves as bisexual tend to be the opposite "predominately homosexual, but more than incidentally heterosexual". (Kinsey 4).
I could speculate that there is more pressure on men to be either straight or gay due to the fact that homosexual men are often assumed to be weak and feminine. Put it this way, if you're already rejected from society then you have less of a reason to hesitate potentially taking on an identity that could bring rejection (For example; if you've identified as gay man for most of your life but suddenly find yourself in love with a woman, then identifying as bisexual isn't that much of a leap. But if you've identified as a straight man and find yourself in love with another man that can be quite scary, going from a majority identity to that of a minority).
Although, having said that it could also be worrying for a man who identified as gay but suddenly finds his attractions to be closer to bisexuality, since some gay men are biased against bisexual men so he'd likely find himself facing new kinds of prejudice.
Interestingly, women who are bisexual but happen to prefer the opposite sex seem less hesitant to take on the bisexual label. Lesbians are often stereotyped as masculine or butch, however the same cannot be said for how society views bisexual women. This is where the main difference lies, bisexual men are often assumed to be gay and in denial (and still somewhat gender non-conforming) whereas bisexual women are typically portrayed in a fashion similar to how straight women usually are.
A frequent assumption made about bisexual women is that they make out or have sex with other women as a way to allure men. They are shown as feminine, and the underlying misconception is that women don't act the way they do for personal satisfaction, but as a means to please men and gain their attention.
Such views are nothing new, female sexuality in the past has been assumed to be non-existent and that women only have sex with men because it makes men happy instead of because the woman enjoys it herself. That all men are hypersexual and women asexual. However, the reality is quite different.
Personally, I am a homosexual/gay woman. Sometimes people assume that I am a lesbian because I must've had bad experiences with men or that I'm a misandrist for some reason. However, not feeling sexual attraction to a certain sex doesn't not mean that you hate everyone who happens to be of that sex. It just means you don't find them sexually attractive.
There are some individuals who refer to themselves as "Political Lesbians" and I think this is potentially where the stereotype of lesbians hating men comes from. In some radical/extremist strains of feminism it is believed that dating men is oppressive and those who believe this refer to themselves as "Political Lesbians" and only date women to make a statement. The main difference between "Political Lesbians" and regular lesbians is that regular lesbians date women because they are attracted to them, where "Political Lesbians" do so to try and make some kind of point.
Now, although some circles believe that gay men are all misogynistic, I would say that the belief that lesbians are misandrists tends to be more common/ widespread in comparison. Women are thought to either be;
A) Straight.
B) Still straight, but acts in a bisexual manner to get men.
C) Straight, but hates men and dates women as revenge.
Whereas men;
A) Straight.
B) Actually gay but in denial.
C) Gay or just dates men because he thinks women are inferior.
