While the practice of thawing and reheating is not the best for taste and texture, scientifically, I can see no way bacteria can survive the reheat process as long as the desired temperature is achieved and consistent throughout the dish.
I think so too-----but for our finger food Christmas Eve I baked some little frozen appetizers that were about 1.5 inch square. I was 'instructed' to bring them to 165 degrees. Each one?
I declined and took a chance.