You're right about it probably being some guy just eating lunch but he probably had slacks, shirt and a tie on so he automatically became one of us evil rethugs to them.
Where the hell is BouncyBall when they need her. If she had been there, she would have jumped out of the bushes and engaged the Rethug in a meaningful conversation about the Chimpus Khan, pointed out all of the evils of the right, and converted him/her to the dark side.