I think the first filesystems had flat layout (no directories),
That is true for MS-DOS 1.0. But Unix had a tree structured directory system from the very beginning (early 1970s). And the directory listing command "ls" was basically the same in the first Unix 50 years ago as it is in modern Linux.
You might be wondering why Traitorapist Trump did this for a Democrat. For the same reason he pardoned Rod Blagojevich (D), which no Democrat wanted him to do. Trump simply wants to normalize corruption everywhere because he is corrupt. It's the only reason that makes any sense. This is another one of Trump's enshitification of the country moves.
https://en.wikipedia.org/wiki/Rod_Blagojevich