Wow some common sense for a change
Yay! for common sense (for a change). Every time someone gets the power to choose what others get to see, we create a power base for corrupt social manipulation.
If you don't like what you see, the answer for changing a society isn't allowing prohibition of knowledge, where someone gets to choose for others, because that power always ends up getting abused.
The people who make the fundamentally flawed association between violent behavior with violent imagery are profoundly ignorant of the real reasons why some people are violent towards others. (Here's a hint, its not violent imagery!). That ignorance is what has to change, if they truly want to change society for the better.