Every article has an intended audience. When I have a complaint like this, I just assume that the audience was somebody else. Mostly I just move on, but sometimes I'll take the time to do enough research that I understand.

As an occasional writer, I think that's great. I like writing 101-level pieces from time to time, but I'd go mad if I couldn't write for a more specific audience. E.g. I really like commenting here because I can just trust that people, say, know what git is and the constellation of common opinions about it. Not only would explaining all that "take effort", but for people familiar, it comes across as boring filler.