> Would you expect a "privacy focused" browser to offer you networking disabled by default

Obviously not, because at that point it can no longer be used to browse the web. (That said, "do no network requests" should be the default idle state of the browser until appropriate user interaction. Allowing CORS is also a horrible default but that ship has long sailed.)

I also disable WebGL in my Firefox profile and this does not inconvenience me in any way. So I do not think WebGL support is as instrumental to browsing the web as you claim; it entirely depends on what sites you visit. (And let's be honest here, a very significant majority of websites does not need WebGL.)