I haven't read Bandy Lee's book, but I think people are missing the point. Everyone seems to be assuming Lee proposed a syllogism:
- People with narcissistic personality disorder shouldn't be allowed to be President.
- Donald Trump has narcissistic personality disorder.
- Therefore, Donald Trump shouldn't be allowed to be President.
But based on what I understand of her comments, this is not the case. She didn't claim to diagnose him with a clear-cut DSM diagnosis, nor claim that persons with that DSM diagnosis can't be President. Instead, she claimed to be able to deduce all kinds of things about him by secondhand observation, and claimed that those things could predict that he would do all kinds of dangerous things, like kill a bunch of people or get a bunch of people killed. Then, when something happened that resulted in people dying (COVID,) she retconned it into her "prediction" in a case of confirmation bias.
And this is exactly what the psychiatrists whose comments about Barry Goldwater were published in Fact magazine in 1964 did, the publication of which led to the Goldwater rule. We forget now that that was the heyday of psychoanalysis, when psychiatrists thought they could make all kinds of deep inferences about a person based on seemingly, to the layman, insignificant external clues, and trace them back to childhood family dynamics. "Based on the fact that this person stands with his left toe pointed ten degrees farther laterally than his right toe and clears his throat before every time he speaks, we can clearly see that he suffers from delusions of grandeur stemming from the fact that his mother didn't change his diaper in a timely fashion when was progressing from the oral to the anal stage" and other such nonsense. This was considered embarrassing to the field of psychiatry, and rightly so.