Most Pokemon that learn cut tend to have sharp claws, or spikes, to help them cut things. Zangoose has giant claws, so frankly I think Game Freak did it on purpose. There are so many examples like this in Pokemon, that naming them all would take ages, but for example, Scyther can't learn fly, despite having wings. This is known as
Game Freak Logic
Game Freak Logic is a strange thing, which, sadly, can only be explained by Game Freak themselves.