Why does it have to be guarded. Manually. Or otherwise. It has info ,& history that wants to be kept secret

There is a rich military history, I recommend talking to a servicemen from the honor guard.

Back in the early 1920's, they didn't have guards and the Tomb looked much different than it does today. It was flat at ground level without the 70 ton marble 'cap'. People often came to the cemetery in those days and a few actually used the Tomb as a picnic area, likely because of the view. Soon after in 1925, they posted a civilian guard. In 1926, a US Army soldier was posted during cemetery hours. On July 1, 1937 guard duty was expanded to the 24 hour watch.