Language use changes constantly. Vocabulary adapts constantly to pressure for good communication. When I was a young man, gay was used as an umbrella term for almost all LGBTQ people, including most trans people. When you said gay, most people did not receive the meaning, "men exclusively or primarily attracted to other men."

Everyone knew, for example, that the New York City Gay Pride Parade and the Christopher Street festival for gay rights featured lesbians, bisexual people, and trans people.

In the decades since, accepted meanings have shifted, and gay has sort of reduced down to only referring to sexual orientation and sometimes only referring to men.

However, as you point out, many people continue using the word gay as something of an umbrella term, even if not as broadly as in prior decades.

We can all get mad arguing about definitions, if we think that's productive. But I for one just try to use vocabulary that my readers understand. If I'm using words that don't mean the same thing to the different groups of people receiving them, then I'm not communicating effectively.

That means I can't play language cop. I have to study what words actually mean to actual people and either use them that way or use effective alternatives that don't confuse anyone.

And to all the wannabe argumentarians? Chill. We humans don't reduce to labels anyway. They can help us understand ourselves, but they are not stand-ins for who we are.