I don't want to be the one to defend UPS, because they're indefensible.

BUT... "blaming the shipper" means that the item was inadequately packed, not that the box was already damaged - and in the case of those wheels, unless there's a lot more reinforcement to the box than it looked like from your photos, they really weren't well packed.

DH received his new camera body today via UPS. A very expensive pro body. The external parcel looked very similar to yours. The camera was fine, because the bubble wrap from the shipper plus the manufacturer's box protected it.