Of course this is correct and I never said something different.
GNU *is* an operating system, and many people are using the GNU operating
system, no problem here.
But the GNU operating system is not complete; people don't use _only_ the GNU
operating system because it doesn't work.
They're using the GNU operating system with the linux kernel, and so the
whole operating system is called "gnu+linux". Your rms quote doesn't deny
that.
When you're running trisquel, you're using the gnu system (this statement is
correct so far) AND the linux kernel .
But we're running in circles somehow.
Important is: rms calls the system "gnu+linux" almost in every speech.