The point is that men who have sex with men (commonly abbreviated to MSM in sexual health literature) have higher incidence of HIV and STDs.
I think your point is ridiculous (from both personal experience and published surveys), homosexual and bisexual men make up a small minority. Regardless though, it's easy enough to say whether or not you've had sex with a man.
And in answer to your question, seeing as I've never had sex with a man (nor intend to), I'm 100% sure that for all intents and purposes, I'm heterosexual.
Just to be clear, there's nothing intrinsically wrong with homosexual/bisexual activity, but there are provable additional risks for MSM.
>In reality, there are 2 kinds of orientations: bisexual, and closet bisexual.
Woke reality-bending. The "everyone is a little bit gay" is perhaps hip and PC but it's mainly wishful thinking by gays who want to coerce straight guys into sexual intercourse.
Why is this relevant? Surely I can be 100% sure that I'm not having sex with men, regardless of how bisexual you think I am.