When you masturbate to 3D, you're masturbating to a real person which is bad because having sexual thoughts over another human being is sin.
However, when you masturbate to 2D, there's no harm done because he/she/it is just a drawing.
Ergo, masturbating to 2D is recommended if you want to stay pious AND masturbate at the same time.
In conclusion, normies are one mean sinning machine because they think masturbating to 2D is for losers, so they vehemently choose 3D. Don't be a normie, masturbate to drawings.