The MPAA is an American based classification board which they determine the age rating of a movie, but does that apply to let’s say K-Drama or Japanese anime containing themes they consider “inappropriate” for American viewers when they don’t take cultural nuance into consideration. As in you can have a “underage” looking character in anime being sexualized but that work gets accused of glorifying pedophilia in the US.
The predecessor of the MPAA is the Hayes Code, which is even worse with censorship as they sanitize the hell out of movie production (love stories barely have raunchy scenes or violent movies showing no blood) but that only applies to productions from Hollywood while foreign movies are not bound by those rules. Can you create a movie similar to the “Serbian Film” while overseas but will it be approved by the MPAA for theater screenings?
I was going to make that point. Especially in the horror or boner comedy genres where being outrageous is the point, movies are often edited for an R rating for theatrical release and then will proudly boast being unrated on the DVD packaging.