I thought at the time, and still do, that it read like a ransom note in a movie, or what someone thinks a ransom note should read like. "Any deviation of my instructions will result in the immediate execution of your daughter." The reference to an organized group. All the "do X and she dies" text. This does not mean that the person wasn't originally planning a kidnapping - there's a possibility that was the original plan if an intruder did it and the plan fell apart like the Lindbergh Baby case - it just means they have been heavily influenced by TV shows, movies, etc. and what they think ransom notes should be. And outside police or true crime buffs, the only exposure most people have had to ransom notes have been through the media. I don't think they would have been "professional kidnappers" if such a thing exists, otherwise the note would have been very short since long notes tend to give away the actual handwriting of the person involved.