Linus had a different philosophy than GNU Hurd and Minix. So it was entirely appropriate that he create his own project to express that philosophy.
Similarly, ngnix has a different philosophy than the apache web server (raw speed vs. features). Xfce has a different philosophy than GNOME3. And so on, and so forth. Debian focuses on different goals than Red Hat, or Slackware. Dismissing all of this as undesirable "fragmentation" is just stupid, and that's my whole point.