In some cases, the editor likely thought pronouns Davey used weren't clear. If Davey said "he," the editor (or writer) figured explicitly making it "Gooden" would clarify who he was talking about, but since you can't put words in a subject's mouth, you use the brackets to indicate "this is who Davey is talking about." The other use presumes the reader might not know who Nelson Doubleday and Fred Wilpon are, since they weren't previously introduced into the story, thus [owners], in this case. Good observation about use of brackets -- it's one of those things about which the usage is implied, but the reader isn't given footnotes on why they're used. Also, [Davey] probably did some [cursing].