Steps to reproduce:
1. Create a new 2D project. Add some sprites
2. Create two gameobjects with Hinge and Wheel 2D joints.
3. Enter play mode. Notice that neither dead RigidbodyHinge or RigidbodyWheel are moving.
4. Change their Rigidbody2D component values. Changed gameobject will start acting according to its Wheel or Hinge joint defined behaviour.

Adding collider to the gameobject makes it start as awake.
Other joints seem to start as awake.