Its /not/ (only) external, as your "disabled" in the same sentence already implies. Fundamental changes have been made that transfer power from the end user to elsewhere without end user consent nor them understanding the scope and meaning of the problem at hand. This transfer was ( partially ) forced by third parties not acting in the end user or Mozillas interest; in fact the opposite is true. Not only damages technical in nature where dealt, but also in terms of good name & reputation since the adversary made Mozilla squander their responsibilities and by extension betray their relationship with the end users. This is a textbook example of howto drive any organization into the ground.

In my understanding, they could at least have fought for this not to get into the W3C spec, but they did not object, according to the blog. This is one the kind of stuff that endanger free internet, which mozilla is supposed to fight for.