The edge was left as it is so that it will pass the 1917 (I think) string test. The rough edge will cut/tear through the string better than a sharp edge (so I have been told). Never done it, just relaying what I've been told during my 23 yrs.
Isn't it about time we ditched that overpriced piece of crap M-9 bayonet? You can argue "rough edge" all you want, but if they're going to sell it to the Army as a 'field and general utility knife' then they might at least make it ground thin enough to actually take an edge. Otherwise, it's an extra pound that just takes up room in my 'B' bag back in the rear. Indeed, the whole idea of a bayonet on an M4 carbine is just silly, anyway. How're supposed to use a bayonet on a carbine, anyway; wave it in one hand like a sword?
