I probably shouldn't bother, cuz you pretty clearly think that you're morally correct, but in more regulated societies it served as a way to ensure a roof over your head and some food or as a way to escape from a dead-end situation. The way the US did it was unequivocally horrendous, but there...
Actually, the whole Isekai concept comes from mythology so it actually has existed for millennia. (Chinese, Japanese, and Nordic mythology come to mind)
As for the rpg-esque systems, that comes from the culture of our time period. It's a pretty universally understood framework nowadays; used so...
Y'all should really give a way for people who want to help, can't find anything listed on your group page, nor any manga, so I don't really know how to get in touch with y'all...