I think the crux of the issue boils down to whether or not pizza is considered a snack. I don’t think anybody would consider two slices a snack.
Sometimes one. I’ve certainly eaten one slice of pizza “to get the edge off”. On the other hand, sometimes I’ve sat down, and eaten one slice of pizza, with intent that this would be a meal.
With the price of pizza going up nowadays, it’s getting harder and harder to classify it as a snack.