What it amounts to is at this time its not illegal to run your own code on a game system. It MAY be illegal to circumvent protections (this will be decided in the courts before long, but the most recent ruling we have is that it is 100% legal to jailbreak a phone). If you build your own development environment from the ground up regardless of what system its for, and whether or not it lets you use it out of the box; its legal unless it contains something copyrighted by someone else.