Who decides? I personally prefer the term typical it doesn't seem so harsh. If someone I love has a degree of 'abnormal', is it my duty to 'normalise' that person so they are not cast out by society? But am I normal? The rule book I ordered must have got lost in the post.
Okay so I agree there must be some rules, some degree of right from wrong that each of us should learn no matter what our 'normal rating' is. My son is Autistic so I will make allowances for his behaviour but I will not allow him to use Autism as an excuse for his behaviour.