Why do m4r ring tones show up in Library in Finder, but do not show up in iTunes?
iTunes uses a database to track the contents of your library, not the file system. Adding the files to the folder isn't sufficient to make them show up in iTunes, you have to "import" them in to iTunes as well so they get added to the database.

To add your ringtone files to iTunes select File &gt; Add to Library... from the menu or press Command+O.

Navigate to where you downloaded the ringtone files and select all of them in the finder dialog box.

Press the Open button to complete the import process.

You should now see them as ringtones in the My Tones section in iTunes.