Is there a law against it? Has nobody else pointed out that they just don't fit within the lines when they park like this?
By definition, if the owners think their car is so square and smart for parking, then surely they can fit in exactly the same space parking the correct way round. I've actually seen instances where there is a perfectly big enough space to park like a normal person, but the owner has reversed in like an utter bell end just to park in this way. Stop it now.