In that he was devout in any economic theory it was capitalism. Crony capitalism but capitalism. He literally made slaves work for private companies, you don’t get more capitalist than that.
The German industrialists of the early 20th Century feared unionism, socialism, and communism. They backed Hitler and funded the Nazi party. In turn, Nazis enacted the Nacht und Nebel slave labor program, Lex Krupp, and allowed companies such as Krupp to take property from conquered nations.
You are right. Those not killed within a week's time were sent to to concentration camps. Many were forced labor (slave) and then moved to death camps.when they could no longer work. My apologies for being unclear.