So, a couple of thoughts.
Have you shot the gun from a solid rest to confirm that it does or does not shot to POA? If you shot it from the rest and it hits where you aim, then it is not the gun. If it does not, either get someone with the correct tool to drift the sight or send it back to S&W.
You said that you should not have to adjust to the gun, it should just fit, or something to that effect. If you pause for a second, you'll see that's just not reasonable. No two people have the same hands. Guns of different models have different grips. Expecting all guns to alway fit perfectly for all people is again just not reasonable. From what I have read many people shoot the Shield, as well as other sub-compacts, to the left. It seems to be, in the opinion of some, to be the nature of these smaller pistols. I don't recall if my Shield is off to the left because I haven't shot it as much as my FS but the FS was off to the left as well until I adjusted my grip to get more finger on the trigger and firm up slightly with my left hand. That brought it in line just fine for me.
Just because several people shot it and it hit to the left does not necessarily mean the gun is off. Sure, it may appear to support the theory but unless at least one of them has shot a Shield to POA, or other sub-compacts, its also likely all shooters and not gripping the gun correctly to make it hit POA.
Yup, it's been shot off a rest.