I'm sure the victims of nuclear weapons and accidents would very much like to disagree. Misinformation (which seems to be the most dangerous harm mentioned) is hardly comparable to these things, even taking into account the expertise needed to create a nuclear bomb or power plant.
Also, the author complains that in the past you could tell what was misinformation by identifying typos. Plenty of misinformation lacked misspellings and grammar mistakes before ChatGPT, and this very article contained a few of its own. If anything, this will stop people from relying on writing style as a way of verifying the validity of a statement (which is silly), and start using critical thinking to do so. In the end, this is the only way to ever find "the truth", especially in areas where you have no prior knowledge as the author worries about. People aren't helpless to good writing.