(I decided that it would be unwise to post a link to the site because I figured it might disturb the more... sensitive posters)
You mean you're (gasp!) censoring the violence out of your post?!
Actually the networks are "cleaning up" the content they provide, but the internet gives one direct access (at least videowise) to much "raw" footage. I think that while video images can be powerful, cold hard printed facts can be even more damming. The problem we have today is everybody just wants a 30 second update, nothing deep.
Anyhow, to answer your question, I don't think that lack of raw video footage increases violence, I think the lack of hard content in news coverage (just where are those pesky WMDs?) that causes people to be less critical of their government.