pizza is hot and has a lot of fats, oils, carbs. White wine is usually cooled, crisp, acidic, and/or effervescence and most can be a little tart, which helps cut the fattiness and oils of the pizza. That is the complementary aspect of it, it is a classic acidic vs fatty balance. Pizza is warm comforting, the wine is cool and refreshing. Also the acidity in the red sauce provides a nice common element between the two, helping to bind the flavors.