re: Dear Zachary: A Letter to a Son About his Father

A documentary is a visual presentation of facts and events, frequently with the object of persuading the viewer. The object of watching a documentary is to get a more in depth understanding of a news story, historical event, or other technical field. Already knowing something about the story or field or knowing the general story and conclusion of the events doesn't spoil or ruin this object.

I've never gotten upset at someone telling me all about a subject or event then recommending a documentary for me to watch about it. If I think the subject is interesting and want more details I look into the documentary. Eta: in fact many conversations I have go like this. It's discussing topics that you think are interesting.

That said, I didn't consider it at the time, but I see now how this particular doc might be an exception.

Eta: for example, right now I'm about to watch the two Escobars 30 for 30. It happened when I was really young, so I didn't know the details until my boss and I were talking about it. He already gave me the gist of all that happened. It sounded interesting, and he recommended this doc. So now I'm watching it. I guess it was spoiled for me.