He wasn't at the party. Jeremy was. At the end of FNAF 2 the phone guy says that you'll be doing the day shift at a birthday party the next day. He also said to stay close to the animatronics. That's why lots of people think Jeremy was the victim of the bite.
And there's also the fact that you have provided no evidence for your argument.
I am losing faith in you decepticon. I think you might actually not be joking about this.
no i'm not kidding at all
there was even a very-recent leaked easter egg image of the incident, found deep within the game files
here you can not only see the pizza, but also the child having their birthday party
however, because Scott never bothered to work on it or thought that players would find it, it was left low-quality