Hi,
it is because it is a child object,
you can parent the grappling, or make a empty gameObject and put them inside next to each other.
What about causing the child as well as the player spin a full 360 degree angle?
Bare in a mind, I do have rigidbodies for not only the empty game object that acts like a parent to the triggering grapple, but as well a object that the player can perform grappling. So in my scene I do add a bumper shaped object that the player is suppose to grab on to and swing.
Like in this game, when you get to 0:23.
Unless a wheel collider does work for that object that makes the player spin.
So what that means is I do have a empty gameObject that has the "grapple trigger" as a child while being attached to the player, but the grapple still does not act like the video above.
RECAP: grapple trigger is the child of the empty object, and that empty object is the child of the player.