What am I doing wrong?

The temp profile doesn't get the about:config preference set.

ben@snapfire:~$ cat /etc/firefox/syspref.js 
pref("network.lna.skip-domains", "*.lubar.me,lubar.me,*.reactivedrop.com,reactivedrop.com,*.megalomanager.com,megalomanager.com");
ben@snapfire:~$ cat ~/.local/bin/firefox-temp-profile 
#!/bin/sh

PROFILEDIR=$(mktemp --tmpdir -d tmp-ff-profile.XXXXXX.d)
firefox -profile "$PROFILEDIR" -no-remote -new-instance "$@"
rm -rf "$PROFILEDIR"

Edit: figured it out. firefox's documentation is awful

ben@snapfire:~$ tree /etc/firefox
/etc/firefox
└── policies
    └── policies.json

2 directories, 1 file
ben@snapfire:~$ cat /etc/firefox/policies/policies.json 
{
        "policies": {
                "LocalNetworkAccess": {
                        "SkipDomains": [
                                "*.lubar.me",
                                "lubar.me",
                                "*.reactivedrop.com",
                                "reactivedrop.com",
                                "*.megalomanager.com",
                                "megalomanager.com"
                        ]
                }
        }
}