Altering RigidBody Constraints affects all prefab instances on scene

Hi all,

I am coming back to Unity after a few years of having used it last, and I'm finding that I need to relearn everything. Currently I am having trouble understanding how rigidbody constraints work. I am programmatically altering the rigid body's constraints, but it turns out that it is altering the constraints on every single instance of that particular prefab. In order to avoid this, I have to compare the gameObject's name to just affect the instance I want. This doesn't make sense to me. Can someone point out why altering one prefab instance's constraints, affects all instances of that prefab on the scene? Here is my code:

 void Update()
     {
         if(Input.GetMouseButton(0))
         {
             Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
             RaycastHit hit;
             if (Physics.Raycast(ray, out hit))
             {
                 if (hit.collider.gameObject.CompareTag("Tile") && hit.collider.gameObject.name == gameObject.name) //if name is not compared, all prefab instances get affected
                 {
                     Debug.Log("You clicked a tile");
                     Debug.Log("The game object you hit is:" + hit.collider.gameObject.name);
 
                     hit.rigidbody.AddExplosionForce(1000, hit.collider.ClosestPoint(hit.point), 5.0f, 0.0f);
                     Rigidbody rigidBody = gameObject.GetComponent<Rigidbody>();
                     rigidBody.constraints = RigidbodyConstraints.None;
                     rigidBody.AddForceAtPosition(ray.direction, hit.collider.ClosestPoint(hit.point));
 
                 }
             }
         }
      
     }

This is working, I just don't get why I need to compare the gameObject's name, unless the ray is so thick that all colliders are hit, but this doesn't seem to be the case, and the Debug.Log() shows that only the clicked object is being hit.