Maybe because AMD don't officially support Fedora 13? Go ask them why - though at a guess, the response would be something like "our customers don't use it much". That of course refers to the fglrx drivers.
There's probably hacks around to have it running on fedora anyway, if you look hard enough.
But if you're going to use a distro that AMD doesn't support, and is known not to support, and is known to stick to the packages available on their supported list (typically Ubuntu), then really you made that choice.
im using fedora 13 with fglrx
kernel 2.6.34
patched xserver 1.8
patched fglrx kernel module
Imho the place in Distrowatch says absolutly nothing about official support by a vendor. AMD work well with Ubuntu and thats it. But have in mind, the "ubuntu" drivers was pre-pre-pre. So if you want to use these drivers, you have to customize the drivers by yourself. Have a look at SID or Fedora or Arch - these distros are bleeding edge.
On bleeding edge, you had to build the most stuff by yourself. For Arch this work fine and stable. BTW - with some hacks from fedora. Have a look at the Aur. Patch and build, its all there.
the new Fokus of FGLRX.... sorry Catalyst is ---> Desktop
mybe the workstation Guys smoke a green spliff and think about there workstations transformed into Desktops... and now they want have Compitz to LOL
RIP FGLRX