A shutter speed of 1/1000 of a second would not be used, even for an outside shot. The image produced would be too dim. There probably is no a setting on 1/1000 of a second on that camera
Even my old inexpensive Nikon D40 has a shutter speed capability of 1/4000 of a second. If you think 1/1000 of a second is not reasonable for a photo in bright daylight looking up toward the sky, then you might not know as much about photography as you apparently think you do. Today’s cameras record digital photos that include information about the camera settings. It should be feasible to find out the exact camera settings by referring to the actual photo as recorded by the camera. Have you researched this to see if the photographer has provided this type of information about the photo? If not, you might want to consider doing so.
Edit: 1/1000 of a second shutter speed is a very commonly recommended setting for sports photography. It “freezes” the action. There is no reason to believe that the photographer wasn’t using that setting for the Trump rally.
It is true. I know more about math than photography. I am going by my memories of cameras in the 1970s. And I was not too much into cameras even then. But as I recall with those cameras, you could go with a short shutter speed, but the image might be too dim. But you can counter that by using a wider aperture, where you would have a bright image with a short shutter speed, but the wide aperture gives a less sharp image. Perhaps with digital cameras you can have the best of all worlds.
By the way, one can look at the photograph by googling "trump bullet streak", go to the images tab and see a photograph with a red oval drawn around the streak.
Well, the answer to the mystery is to be found by consulting the professional photographer who took the picture. "What was the shutter speed of the photograph that he took?". I bet a professional photographer could give us the answer even a couple of weeks later, or a year later. He would know what shutter speed he was using that day, at least approximately, which would answer the question. If he was using a shutter speed of around 1 / 1000 th of a second, then I guess it would have to be a bullet. The press should get onto looking into this. They only have to question one of their own.
But I don't think so for the following reasons
1. Trump being reluctant to release the medical records of that day, which would prove at a stroke, that he was "heroically" struck by a bullet.
2. I don't know much about camera. But I read a post from someone who does, I believe. He claimed that a super high shutter speed was not used, because the image of Trump's head is blurred. This can be seen in the "Make America Great Again" slogan on Trump's hat (well, at least the left part of this slogan) being blurred, caused by Trump moving his head when the shot was fired.
3. A fantastic coincidence that the shutter was snapped just when it was, to within a millisecond of when the bullet struck the ear. If it was a fragment moving a tenth of the speed of a bullet, it would still be a coincidence, but not so fantastic.