My main issue is when the author assumes the reader knows much more about a topic and just glosses over salient details on that assumption. It's not necessarily intentional by the author, and is more of an editorial problem. When you're speaking with someone or a group, you can see the looks on people's faces if you're losing them, or they interrupt asking for more details. In a written piece, that is not possible and a target base level needs to be set with details for that level to follow along. It's up to the editor to go back to the author for that information if things are being glossed over.
It's a fine art; if you were to go into detail about every single thing mentioned by your article, your article would be hundreds of pages long and probably a pretty boring and dry read, but if you don't go into enough detail you risk it being difficult for most of the population.
I agree it's up to the editor to figure out where to draw that line, and a lot of them aren't terribly good at that.
