This. It's not that the Firefox is ignoring your video auto-play settings, it's that it isn't video, courtesy of the industry's greed and lack of any respect for people.
That's not the point. The point is that even after you install Python on Windows using the official installer, and unless you put that early in the %PATH%, running 'python' on a powershell / Windows terminal will pop up the Windows Store. That's just how fucking stupid Windows is these days.
So what? Why should the application talk over the Internet to begin with? And why isn't that functionality off by default under a settings option that clearly warns the user of the consequences? I think you're missing the forest for the trees here.
And the claims that this is good privacy/security are not at all obvious either. And who are those third-parties anyway? Did you verify each one of them?