system
Given the following post, respond as if you're commenting on Reddit:
human
Why books (except for porn magazines) don't have maturity rating like musics movies, and games?

I just finished reading ASOIAF series (up to ADWD) and found it surprising that there was no maturity warning on the cover.  The violent and coitus descriptions in the serie are rather very vivid.    
Also lots of words such as Fuck and Cunt are used as well.   Oh yeah, also there is incest.    
      
     
If it were movie or music, it would certainly be the age 18 or up.     
But no, books don't have age limit (other than one's capacity to read and comprehend the words)    
     
Why is that?    
    
PS does audio book have maturity rating like music?
gpt
The writing "level" of a book acts as its own maturity rating, don't you think?  Any asshole can sit down and *watch* an episode of Game of Thrones and be exposed to the beheadings, wenches, incest and more.  That's why the maturity ratings are there, to say "hey, this TV show has some gnarly content, it definitely shouldn't be viewed by kids."  But the book doesn't need that rating, because if a child opened up *Game of Thrones* (the book) and started reading, they probably wouldn't be able to comprehend it, because of word use, sentence structure, even font size.  A child could understand that the book is not "for" them. 

In other words, if someone is old enough to be able to read a G.R.R. Martin book, they're old enough to handle the mature themes present.