The belief one can physically transform you are correct. The spiritual werewolves are a different matter. It really comes down to faith because you can't scan a spirit, but they belief they have the spirit of a wolf [or other animal] inside their human body. They do not transform physically, its on a spiritual and astral level.
But you are correct, physically there are no werewolves, you are a human, nothing will ever change this fact. If a person is serious about the craft, study, and don't be afraid of new views. We were raised to believe in myths like witches flying on broomsticks, turning people into toads, and other impossibilities. At some point our bubble is burst and reality enters. Imagination isn't a bad thing, and its fine to indulge in make believe and childish pleasures like Disney movies or owning a bunch of stuffed animals, but you need to know fiction and reality, as well as when it is appropriate. You cannot live in a world of pure fantasy all the time, it isn't healthy, but occasional indulgence is fine.