A reenactment of a historical tragedy is one thing. A game that recreates the assassination of an actual President and casts the player in the role of the assassin is another.
What's next? A game that encourages players to step into the shoes of John Wayne Gacy, and scores them based on how closely they can recreate his killings? Or maybe a flight sim called 'Tower Toppler', where you pilot planes into the WTC and try to hit the right spots to bring them down, with scoring handled by a 'death toll' counter? After all, those incidents have been the subject of reenactments, too, so there's nothing tasteless at all about building games around them, right? I can't believe you actually see nothing wrong with this.