Because taking away mindshare instead of consolidating efforts hurts all parties. Competition is often good when done for very good reasons, iojs vs nodejs, proprietary goals vs purely open source. Their goal is the same goal as many other projects however, instead of supporting those projects they are releasing their own which will likely have to go through a LOT of growing pains to compete with current projects. Simply releasing your own OS (written by two guys) seems naive at best and arrogant at worst.