> I think the people who need those abbreviations spelled out are not the target audience of the article.

Probably. But I like reading a lot of articles I'm not the target audience for, because I like learning things. Writing it like this excludes a ton of people who might not already be insiders to become insiders.

Maybe that's a choice, a way to keep knowledge away from outsiders, to feel better about knowing that people who read your article are cool like you, and that's fine. But if the goal is to educate and reach a broader audience, it isn't effective.