The criminologists and psychologists (as I said before) are pretty much in agreement that some rampage shooters are influenced by past accounts. They study fan sites for Columbine and VT. They buy gear from the stores that sold such to the previous killers.
The 'if it bleeds, it leads' media view will keep up the flow. Every time you see a crying loved one, it reinforces some of the shooters who want to generate that pain - even after their own death. It is either that they enjoy as a revenge fantasy or want to teach society a lesson - and it can be both.
Of course, the 1st Amend. protects such stories as well it should. Whether media should use discretion is a market place issue.
However, the motivations are complex and just fame or antigun plots don't capture it.