It could also be that the fork was damaged before it was put in the box -- that'd be my guess, unless the box was obviously damaged. I've shipped and received a lot of bikes. If it happened in transit, nothing inside the box bent your fork; the force came from outside, and the box is your key witness.

On a side note, those plastic things that get shoved into the fork ends are a waste of material and effort. If something is crushing the box hard enough that that little piece of reinforcement comes into play, that shipment is an insurance claim.