Is that "normal" these days?
I dunno. It seems a little bizarre to get a tattoo of a character from a crappy movie no one will remember in fifteen or twenty years.
Ultimately, what does it matter? There is no just way to prevent this kind of thing. Should we lock up everyone with bizarre tastes in tattoos, or everyone who cuts themselves (which, I can assure you, is a *very* common, if somewhat deviant behavior)? Everyone who quits a job abruptly, or everyone who drops out of a grad program?
It's a little odd that he was being reported in the "ordinary guy gone nuts" mode, but that's just the media works. They created an image to go along with what they figured out about him in the first hour or so after the shooting, and it matched his yearbook picture.
It's all just media craze anyway, that is ultimately pointless.