The drafts throughout history in many countries have always been done this way to varying degrees. It is partially seen as a way to mow the lawn as the elite class would see it. Whoever the undesirables are at that point in time get to go into the meat grinder first. Most recently, Russia has done this in Ukraine… Sending convicts, minority groups, poor people, etc, to the front line. Modern systems now would allow specific targeting of a draft to political opponents, specific areas of certain groups, and so on.