> Are the critics right then? Has Linux so fragmented (like Unix did) that "Linux" users must have these arguments over which distros should be supported? Or is this just another excuse to attack Ubuntu.
It used to be that Linux distributions differed quite a bit for very significant reasons. Some provided configuration tools and interfaces that were proprietary in a attempt to do the 'value added' approach to getting licensing costs from linux. Some people dissagreed about how you should approach package management systems and so on and so forth.
Nowadays everybody uses pretty much the same stuff. The major differences are going to be Redhat configuration tools vs Debian's package management system. Other then that people are switching to upstart, they are using network-manager for desktops, dbus, packagekit, policykit. Pretty soon they should be using about the same initramfs environments and so and so forth. Much more the same then different.
IMO one of the major goals for distributions is to eliminate the differences in the so-called 'Linux plumbing' and end up using, more or less, identical systems on the low-level. Then use the same core as a basis to then branch out and do their own thing. Update packages, experiment, etc etc.. but always each time they do a release they re-base off the same core system that they share.
This, I think, will end up going to make application developer's (open source and otherwise) lives a lot easier, as well as system integraters and people that need to document how the system works for normal folks.
As far as Ubuntu-hate goes. It's pointless and misdirected.