I note that it wasn't "GNI" it was GNU or he would have started with LISP.
The fact is rms started by wanting to hack/rewrite Gosling EMACS as it had been released and some of the other C versions were at the same time a little less open to him as a starting point. Since it was not in LISP, he needed to write a C Compiler (which I still think is the #1 positive thing from the Gnu project and in the end, I believe that it was others that really made the compiler the success, not rms other than he tirelessly championed it). The reality is that the Gnu team quick set out to rewrite the UNIX tools and used Trix (a UNIX clone) as the original OS. Hurd did not come until later and in the Linux became the kernel it lived upon (as Jon says, it's Internet/Linux not Gnu/Linux).
Sorry, IMO, rms tried to 'pee on Unix to make it smell like ITS' - not surprising as you say. But pretty darned arrogant none-the less. The results makes using many of the tools "astonishing" to everyone else.
+1 to Jon's comments.
"Even if, as some believe, the GNU approach was superior, any possible benefits were outweighed by the UNIX community’s huge loss of productivity that resulted from the fragmented ecosystem."
Amen brother Jon, and this week's free will offering will be sponsoring ....