The ratings were between 6 and -6.
In the first case : He gave reality shows a rating of -6 points and cartoons a rating of 6 points.
This means : The carton rating was higher compared to that of the reality show by : 12 points here.
To get this you perform subtarction ;
The rating for cartoons - The rating for the reality show
6 -{ -6} = 6+6 = 12 points higher