I think the Government have legislated in such an extreme way to take account of all the idiots and boundary pushers out there. The best thing is to not analyse the whys and wherefors as its not worth the effort - rules are rules and its up to you whether you follow them.
As a newbie to pig keeping when you register DEFRA send you an information booklet about keeping pigs and it has very clear rules on what can and can't be fed so at least all new people have the information.