メモ：MACのシステム環境設定からのアンインストール
System Preferences looks in /System/Library/PreferencePanes, /Network/Library/PreferencePanes, (if you’ve set that up for your local network), /Library/PreferencePanes, and ~/Library/PreferencePanes (~ is short for your home folder) for the preference panes it displays. All of the Apple-supplied panes are in /System/Library/PreferencePanes, and third-party ones go in one of the other locations (depending on which set of users you want it visible for… for a single user at home, there’s not much difference).
ということなので、これらのフォルダから、消せばいいらしいです。