I would be a bit surprised if this is true, because it implies that when you're writing code that will be formatted you do not think of the reader's experience.

This could be the case if you have extreme confidence in the formatter, but I have def seen some very funky black outputs. It seems like when writing people will likely do so with a model of how black will yield the final code in mind. (Eg "if I add more characters to this one line list statement, it will get exploded across 5 lines", and affect readability, etc..)