It is above their journalistic paygrade and the system doesn't have a 'duty of care' principle because the right to free speech wins out in the game of legal top-trumps in the American legal world.

The Washington Post gave their pen (and market credence) to a non-journalist to write an opinion piece - that's not just reporting self-incriminationary words (perfectly fine), it's giving a soapbox to someone who has a version of the truth distorted by their own poor mental health.

Would the Washington Post allow someone with paranoid schizophrenia an op-ed? Would they publish it simply because it was fine to allow that person to self-incriminate on any number of crazy theories that could lead to a libel case? There has to be some sense of due diligence at play surely?