Leaving off the rest of the conversation, something I wanted to clarify here is that we're not actually talking about sexual orientation… that's a separate issue and concept. As mentioned, there wasn't really any such thing as distinctions between "sexual orientations" in old Japan… homosexuality (as understood in our more "modern" Western society) didn't really exist… nor, for that matter, did heterosexuality… or anything else. Each and every person would simply engage in a number of differing relationships, of various forms, with a number of people of each and either gender at various stages in their lives, for different reasons, and in different circumstances. If that relationship was between a boy and a girl, a man and a woman, an older man and younger woman, an older woman and younger man, two boys, two girls, two men, two women, an older man and younger man, an older woman and younger woman, or any other configuration you can think of, it really wasn't a "thing" that needed to be defined as anything beyond a "relationship"… whether it was sexual or not.
What is actually being spoken about is the idea of a sexual bonding between samurai (and other cultures, such as the Greeks, including the Spartans). This is linked to interpersonal connections… and is always simply about one person and another. Probably the closest representation in modern popular culture is either Brokeback Mountain or The Crying Game… both films where characters who would have identified themselves as "straight" (or "heterosexual") find themselves in situations where they are emotionally driven towards someone of the same gender… the primary difference being that they have to overcome the internal and external societal pressures and personal self-identification of the characters themselves, rather than to simply be in a position where they could accept the way their attraction was taking them.
It's not even about "homosexual" acts… that's a part of it, sure, but it's really the most superficial aspect of the whole concept. It's really about individual's bonding… being as close as they could be. It's the same in many high-stress intensive environments or situations… to look again at a modern popular culture example, look to MASH… Hawkeye and BJ were incredibly close… bonded as tightly as possible… and professed love for each other (and other characters) many times… sexualised love is simply one expression, Hawkeye and BJ didn't take that route, but there were likely a range of societal and circumstantial reasonings for that… not least of which was the presence of the nurses!