If admins want to block things then they should use ESR version of Firefox..
But the standard version of Firefox should not have these enterprise functionality.
This way admins can pre-install Firefox ESR and control them on computers that don't allow installation of applications.
However we have admin right to our computers to install applications we need.
meaning we can just compile a firefox clone to get around this grouppolicy stuff,, but then we might not update our clone very often,, so that can be a security problem with outdated clones.
Again please remove the enterprise functionality from standard version of firefox so we can use an secure and uptodate version.