This is flawed logic.
Only a sufficiently massive craft that could completely obscure an earth focused camera might be detected. This is because the cameras are focused on the earth's surface and anything in the near field, unless it can completely obscure the light that the earth facing lens collects to produce the image, wold be undetectable or only be able to make a shadow in front of the image. At best, an object in orbit passing between the satellite and the earth would manifest as a slightly darker patch crossing the field of view and would be completely out of focus. Think of a photographer at a zoo focusing on an animal behind a chain link fence, you can't see the fence if the magnification is high. If the magnification is high, as it is to read a car's registration plate, it would never be able to focus on any object passing between the satellite and the earth unless the object could completely obscure the light that the satellite needs for focus. In that case you would only know that there had been a massive object pass between the satellite and the earth but you would be completely ignorant as to what it might be as the cameras are generally fixed focus and digital zoom or mechanical zoom is done on the fixed collection frame.
That;s why there are no pictures from any of the 12,000 high tech platforms in space. Not that they haven't had it happen but that even when it happens, its undetectable.
Yea yea, I know: Tl;dr (it doesn't fit yout world view)