I see no good reason for lights pointing up into the sky ,lights surrounding and illuminating a flag where 99% of the light just pollutes the view.
Don't put a huge light in your backyard that forces me to use blackout curtains to sleep at night.
Sorry, I see every reason to illuminate the US flag if you choose to fly it at night. When that light goes out, it goes out for generations...at least until some future generation figures why it glowed so brightly, yet so briefly, in the history of man.