Linux would be much farther along on the whole "world domination" plan if they could just come together and play nice with one another. But no, we can't have that; everyone has to have a different idea and thus the reason why Linux is the chaotic mess that it is today.
The only real way Linux could be classed as fragmented is if you run several distro's at once. Pick one distro, make it a popular one and learn it well and there is no fragmentation.