Silly me. When I see a legal document with a heading "Factual Background" I have a certain logical expectation, based on my knowledge of the English language. Of course, John Roberts should have disabused me of that, but, I guess I am a slow learner.
Completely understandable and natural. But in a complaint, the function of that section is to spin - carefully select facts, etc. to make it read like your side should win.
The other function (aside from propaganda) is to give a reasonably concise narrative of what happened, setting the table for the specific allegations and points of law that follow.