Kees also filed an upstream bug and the very first line of his Fedora bug report points to the kernel.org report, which points again to the Ubuntu bug.
I see your point that the posting to the Fedora bug-tracker was redundant and perhaps wasting people's time, so far as Fedora's processes go. However, it does NOT seem like Kees was trying to sneakily get RedHat to work on Canonicals' bugs. All it looks like is that he's trying to raise awareness amongst the relevant technical people about a fairly serious ext4 performance regression, in an open, technical manner.
So the "Go fix your own vendor bugs, nyeeh nyah!" responses still don't sit quite right with me.
FWIW, I'm a general free Unix/Linux user. The logos and branding on my preferred Linux distro say "Fedora", but the software I use is maintained by engineers/hackers from a *variety* of vendors, including Canonical.