I'm from the UK. I've always considered this ridiculous, like the MPAA rating system in general. I don't understand how a horror film clearly aimed at adults like The Sixth Sense gets a PG-13 rating (here it's a 15 certificate, which is a mandatory lower age limit for admission), whilst a drama like The King's Speech or The Power of the Dog get an R rating purely for the extra f-words (in a speech therapy context) and brief entirely natural nudity, respectively. Both are rated 12A here, which means children under twelve can attend if accompanied by adults.

At the upper end of the MPAA rating system, they often censor sex for ridiculously puritanical reasons, whilst the uncut versions play over here with 15 or 18 certificates. I don't understand why American adults stand for being treated like children in this way. We don't. Anyway, just an observation. :)