This connection may seem weak, until you consider the rest of the wording on the Badlands card.
It is extremely likely that the SLA letter (2/3/1974) and the subsequent kidnapping of Patty Hearst the following day (2/4/1974), along the Badlands card (5/8/1974), both had links to William Randolph Hearst. It also seems credible that the Badlands card, through the subtle use of language and an acute awareness of history, tied Orson Welles to William Randolph Hearst by referencing "consternation", "cutting the ads" and "A citizen". The author of the SLA letter, Badlands card and Red Phantom letter was almost certainly not the Zodiac Killer, but somebody within the Symbionese Liberation Army, or closely allied to them.
MORE READING: THE PHANTOM ZODIAC LETTER ON JULY 8TH 1974