Creation of a Space Marine

http://wh40k.lexicanum.com/wiki/Creation_of_a_Space_Marine

I had been wading through the mess that is the 'Warhammer 40,000' canon, when I stumbled upon a most interesting article. Said page appeared to detail, to a very educated degree, the various modifications inflicted upon a human being during the creation of a Space Marine.

Being an adamant player of this particular army (former-Ultramarine-turned-Grey Knight, in case you were wondering), I approached the article with a healthy amount of skepticism. Surely, with a franchise so plentiful in contradictory fluff and shifting details, there would an oversight within this layout of information.

Much to my gradual amazement, the material in front of me appeared to not only consist of solid details, but it also lacked needless ornamentation, making it accessible to those newly-inducted into the ways of the grim millennium. The list, though brief, would serve well to inform those thirsting for a more complete understanding of this popular army/race.

However, this collection of impressive biological modifications also happened to present a rather puzzling question in itself.

With a single entity possessing this extent of biological engineering, how does one calculate its measure of humanity? Should such a being even be allowed to keep the classification of 'human', given its nigh-supernatural abilities?

...Perhaps I'll look into Orks, instead. They seem to be philosophically straightforward.