I think you are misunderstanding the description. But saying that it is rather confusing. I had to read it a few times.
I think when they say it is 'grinded left side' that is the r/h axe with a flat or 'slightly concave' grind on the left and a normal bevel on the right.
That is how I read it anyway. I Think !?
The Large Carving Axe, Grinded left side, has a short bevel face on the right side of the edge, if the axe is held in the right hand with the handle down and head up. The left side of the edge has a longer, slightly concave bevel face, which provides excellent support when carving.
The Large Carving Axe, Grinded right side, has a short bevel face on the left side of the edge, if the axe is held in the left hand with the handle down and head up. The right side of the edge has a longer, slightly concave bevel face, which provides excellent support when carving.
Right-handed persons normally use Large Carving Axe, Grinded left side, and Left-handed persons normally use Large Carving Axe, Grinded right side, while the longer slightly concave bevel face come near the wood and therefore provides excellent support when carving.