It's NOT Unrated, it's Not Rated
Not rated (NR) is a movie not submitted to the MPAA for a rating.
Unrated (UR) is a movie that has been previously submitted to the MPAA for a rating and has since then been re-edited (new footage put into the film and such). Most of the time, this new footage will not effect the current rating whatsoever, so it would be a waste of time (and money) to re-submit it back to the MPAA, therefore it's "Unrated".
This movie has not been submitted to the MPAA for a rating (http://www.mpaa.org/FlmRat_SrchReslts.asp) and so it is NR, not UR.
The use of the UR tag is usually to coax you into buying it, when half of the time it's nothing more than a minute of extra dialogue cut for pacing.
It's not possible to have a mature conversation with a Dimwit. Everyone knows that. Except Dimwits.