That second article does a good job of identifying the core element here. "Straight," "gay," and "bi" aren't platonic sexual orientations that come down from the heavens fully-formed; they're socially constructed, and largely unique to our current time and place in history. There are many cultures where sex between same-sex partners generally took place inside some kind of societal third-gender arrangement, or where it was typically seen as belonging in a certain phase of life, or where it was the expected way to have sex outside marriage so as not to produce bastards. Lots of people that we'd view as "straight" in our society participated in all of those cultural patterns.
When we talk about "gay" or "straight," we take the assumption that they describe a preference of attraction that is absolute, but it's rarely that simple in reality. Some men only want a relationship with a woman but find other men attractive for no-strings sex. Some only want women as their primary partner but want to participate in MMF threesomes. Some might be straight except for one specific man they're into out of whatever random circumstantial chance. Some might be dating a woman who eventually transitions to being a trans man. Some aren't interested in men specifically at all, but are willing to sleep with them because they're the only people situationally available (all-boys schools, military, prison) or just more accessible in general due to a heavily gender-segregated society. None of those really make sense to categorize as "gay" since they're all groups who are interested in women sexually to some degree, lumping them all in as "bi" elides some pretty significant differences between them, and in many cases there'll be a point in their lives where they'll never seek out or have sex with a man again afterwards. That's what drives the sociological idea of accepting a self-identification of "straight" despite the awkwardness.
That's not what it's saying at all. The point is that right now, any gay person in our society has always had to actively discover and reaffirm their own sexual identity, but someone can be straight without even ever considering it. I would agree that there are plenty of men who are straight, who might not ever want to act sexually with any other man, who would still benefit significantly from examining their own sexuality and trying to understand as thoroughly as possible what they're attracted to and how it intersects with their identity.