I don't think it's really avoided in film is it? I'd imagine it's avoided in video games for the same reason a lot of controversial issues are avoided, and as a lot of people have said, in film it tends to be used as a rather dramatic point in the story, rather than something that just happens and is ignored from then on. In video games, if you just ran about massacring hordes of children for a while, before then moving back onto the story and being the hero it wouldn't quite work
@benpicko: It came out in theaters a couple months ago, but got a surprisingly limited release for a Miyazaki film. The closest theater to where I lived that was showing it was like 45 minutes away so I decided to just wait for the DVD which is not yet out in the USA.
Oh right, seemed like a pretty wide release in the UK. Same with Boyhood though from what I've heard. There are only like 3 cinemas showing it in Canada and it's all over England