I think there's something to be said for a game like this. If you listen to the punditry surrounding gun control as it relates to something like Sandy Hook, it's easy to see why a game like this exists and is - dare I say it - necessary. The pundits sicken and anger me more than this game does, and I find them to be more disrespectful of the dead and the grieving in their pursuit of ratings, votes and soapbox-masturbation than the developer of this game could ever be. I feel that
they're the target of this game, because this is the video game equivalent of the verbal/political game those people play every day when they pontificate.
People hypothesise about how different kinds of law pertaining to gun control could have prevented or altered the outcome of Sandy Hook (let's not get into that debate here). A game like this takes those ideas and puts them to the test, it makes people have a more visceral "hands on" view of what
they propose, offering an insight to their own world view which they'd never otherwise have. Great art holds a mirror up to society, and that's what I think a game like this can do. In its most significant ways it's not even about the atrocity itself.
Don't get me wrong, The Slaying of Sandy Hook Elementary probably isn't a great example of the power a game can have in a debate like this (excepting that it raises the question quite effectively), and it sure as hell ain't "great art", but a game in which you take on the role of a real-world killer and re-enact what he/she did can have value.
JFK Reloaded and
Super Columbine Massacre RPG! are perhaps better examples.