I don't need the architect's permission to add on to my house. I don't need the hardware designer's permission to add on to my Amigas. I don't need the software designer's permission to add on to my software, particularly when the operating system was designed specifically with that capability in mind.
There are many friendly, open, and reapsonsive developers in the community. There are also those who operate as a professional cartel, stonewalling attempts to effect change. It's sad, it's counterproductive, and it's demoralizing to those who donate time and resources to the betterment of the community without any desire for compensation.