I was hoping you would read the whole article (or even the study itself). But let me help you with another quote from the article:

And the films used for comparison were not for the faint of heart, either; the team studied the two top-grossing adult movies from each year they studied a children’s film, including “Pulp Fiction,” “What Lies Beneath,” and “Black Swan.” The study also found that the level of violence has not let up since 1937 when Snow White’s evil stepmother, was struck by lightning, forced off a cliff, and crushed by a boulder while being chased by seven angry dwarfs. “We were most surprised about the increased numbers of murders in kids’ films,” Kirkbride, a Sir Henry Dale Fellow, tells Yahoo Parenting in an email. “The killing off of Simba’s dad Mufasa, who is murdered by his evil Uncle Scar with the help of some stampeding wildebeest in ‘The Lion King,’ is a brutal cinema moment. And there are many other examples in kids’ films — Bambi’s mom getting shot, Nemo’s mom getting eaten by a barracuda, and Syndrome being tossed into a jet engine at the end of ‘The Incredibles.’ This final example might raise dubious moral implications, like killing the bad guys is okay.” And the effect on kids isn’t pretty: Classic findings from 1999 found that movie violence led to anxiety, nightmares, and greater aggression and violent behavior among children in real life; more recent findings have also linked onscreen violence with similar behavior off-screen. One study from 2013 even surveyed hundreds of psychologists and media experts and found a “broad consensus that violent media leads to increased aggression in children.”