Can't shoot towards mouse click point

I'm making 2d space game from side-view, and i wanted to add some weapons that would shoot on x and y axis towards the point where the player click the mouse.I found something so i tried this:

 var hit  : RaycastHit ;
     if(Input .GetButtonDown ("Fire1"))
     {
          var ray : Ray  = Camera .main .ScreenPointToRay (Input .mousePosition );
          if(Physics.Raycast (ray, hit, Mathf.Infinity))
          {
              var shootProjectile : Rigidbody = Instantiate(projectile, GameObject.Find("spawnPoint").transform.position, Quaternion.identity);
              shootProjectile.AddForce (hit.point * projectileSpeed);
          }
 
     } 
 }

It shoots well if i click in to empty space, but when i click on object with collider, it shoots in very weird directions...I spend day and half finding a solution, but I didn't find it. I tried many things, just do'nt work. Can anyone help me? The best would be to post repaired code and explain why my code don't work :)