It is often said that the statement “Straight men who have sex with men” is an oxymoron because any man who has sex with men is at least bisexual. I disagree.
It depends on how you want to define sexual orientation.
First of all we need to realize that most gay men have had sex with women, and many continue to do so. And all the talk about married gay men. Most lesbians have had sex with men, and many continue to do so. So none of these gay men (almost all of them) who have had sex with women are really gay? So none of these lesbians (almost all of them) who have had sex with men are really lesbians?
I do not define sexual orientation on behavior. Behavior is one thing and orientation is another. They tend to line up pretty well but not completely and not always.
Orientation is the largely biological tendency or setup of what at least men and many women are attracted to. A lot of lesbians appear to be biologically set up to be this way.
Behavior is who you have sex with, which usually lines up fairly well but sometimes not completely with orientation.
It’s well known that when women are not around, straight men (men who are attracted to women only and men not at all) will have sex with men.
Many lesbians who have little or no attraction to men nevertheless have sex with them, often quite a bit of sex. Note how many prostitutes are lesbians.
Many straight women will have sex with other women in all-female institutions if there are no men around.
The people engaging in this opportunistic homosexuality are often not bisexual; instead they are just deprived straights fulfilling their sexual needs with the same sex as the opposite sex is not available.
The only men who are bisexual are those are who attracted to both sexes.
We also get into how people identify, which is important. I know women who have sex with men and women but identify as straight, as they only have relationships with men. I know a woman who identifies as lesbian though she has sex with men too because she can only fall in love with a woman. This woman was a 25-75, which normally should mean lesbian-leaning bisexual, but she defined herself as lesbian.
Many men are 90-10’s or 80-20’s (very straight leaning bisexuals), but as they have no interest in and refuse to act on their male interest, they identify as straight, which is reasonable. Many women who define themselves as straight to me tell me that they have some lesbian interest but refuse or choose not to act on it.
The GLBTQWTF SJW’s have been wildly antiscientific about sexual orientation since forever. You almost never read anything truthful, factual, or scientific about sexual orientation in the popular press and increasing even in academic journals. That is because the debate has been taken over by GLBTQWTF SJW’s who have twisted all the science into propaganda and lies for their nonheterosexual orientations.
There are very few clinicians or scholars who are doing actual scientific work in sexual orientation nowadays because GLBTQWTF SJW’s are utterly hostile to even having science look at the question.
Joe Kort is a gay psychologist. He is one of the few humans in the US who is actually doing real work on sexual orientation. He has written a book called Straight Guise about straight men who have sex with men. He lists all the different reasons why they do this.
Kort defines them as straight because they are not attracted to men or men’s bodies.