I think people are affected by what they consume--like food affects your physical development, entertainment seems in some way to affect your social/moral/emotional development. For instance, Jeffery Dahmer mentioned in an interview before his execution that pornography played a significant role in developing the urges that ultimately led him to kill women.
A positive example in my own life--as a child, I never found myself inclined towards racist beliefs, but never considered racism an issue of much concern. I just thought it was something my folks generation was concerned with. Then, around age 12, I watched Blazing Saddles and found myself suddenly aware of and sorrowful over the depth of suffering caused by persistent racism. It was the scene where the elderly woman brings the sheriff a pie at night, for those familiar with the movie. It broke my little 12-year-old heart.
Speaking of Blazing Saddles, I need to go re-watch that. Such a great movie.
Censorship is not the answer, but as already mentioned, better tagging and labeling would be a great help for all involved. Anyone remember search engines in the mid-90's? You couldn't click any search result without a 50% chance that it was a pornographic website hiding under a title like "50 Ways to Win at Chess" or "How to Fix Your Transmission."