Folding a hand is not playing it? I would define any action (fold, call, bet, raise) as a play. You would almost certainly define folding on the river as a play, why not folding preflop?

Because there's no loss or no gain when you fold preflop and you don't even see cards, so it's more like abstaining completely? I don't know, I see your point though, the metaphor was stretched a bit far.