That is so true! Some m rated movies are just as bad as the news, as the news shows you murders that are real and let children be aware that these things are actually happening whereas in movies, tehy have a high understanding that these things are made up.
I believe that it all depends on the maturity of the child. I picked out 3 movies in my dvd cupboard that were rated M... the Pursuit of Happiness, Charlie's angels and Ghost Whisperer. Now, I know some 8 year olds that have seen these movies and not been given nightmares or copied bad language from them. However, some parents to not agree that their 12 year old children are ready to watch m rated movies as some of them have mild coarse language. All up i think that the majority of 12 year olds should be able to watch m rated movies as the maturity and understanding of them is at a very high level.