I also thought that retailers were not allow to charge your card until dispatch. That was definitely the case a few years ago anyway.It is not a pre-order if the product is already released. What they are doing is taking back-orders. Both concepts are 2 entirely different things.
A pre-order is when a product is not released yet and you are ordering it for release (this term also does not carry a negative connotation)
A back-order is when a product has exhausted supply and is currently out of stock (this is interpreted more negatively)
By taking orders and calling them "pre-order" instead of "back-order" is nothing but deception.
Using preorder is definitely fishy.