Note that the Tanenbaum-Torvalds debate was in 1992, over thirty years ago. The security of computer systems might have improved since then, but the fallout of security issues has massively increased. Managing your bank accounts wirelessly on the Internet from anywhere in the world with a thin, battery-powered device that fits inside your pocket was a pipe dream (and no one could've possibly imagined that an Internet-ready smart toaster could compromise it and steal your money on your accounts).