Those arms can do a bit of damage but it's a feint, a scare tactic to make you step back, it's the back legs you have to worry about. They have very thick padding on their stomachs, humans do not.Yeah this one is built like a brick wall. A 7 feet tall brick wall.
Just because an animal is not afraid of you does not mean it's tame. It just means that it has no need to be afraid.