A UIGestureRecognizer is to be used with a single view. I agree the documentation is spotty. That UIGestureRecognizer has a single view property gives it away:
view
The view the gesture recognizer is attached to. (read-only)
@property(nonatomic, readonly) UIView *view
Discussion You attach (or add) a gesture recognizer to a UIView object
using the addGestureRecognizer:
method.