Edit: Here’s a link to what is most likely the real manifesto: https://www.kenklippenstein.com/p/luigis-manifesto
Ken Klippenstein is a very reliable journalist and this version of the manifesto contains the snippets that have been released by law enforcement. Also, considering the thing was hand-written, that very long version involving his mom is dubious. (And there’s not any good evidence that his mom is in anything besides decent/good health)
For me, it’s not the professional reputation, but the second that kind of thing gets tagged onto a patient’s chart, it becomes extremely hard to expunge. There are a lot of patients with mental illnesses (some which are misdiagnoses) that face significant problems because of that diagnosis. If a chart gets flagged with “homicidal ideation” at any point, that patient will forever be flagged as dangerous and people will be suspicious of them immediately.