Soldiers are, in a sense, slaves. A standing army is a vast apparatus under direct control of an executive.
But, the opposition to standing armies is long forgotten. We also forgot the reason why only congress was given the authority to declare war, which has become dead letter, and these ideas considered quaint and outdated. But 1776 wasn't that long ago in the history of human governments, and the history of human governments is the history of abusing power.
"Not to know what happened before you were born is to be a child forever." - Cicero