My experience with Windows 9x matches GP's claim. If you had a broken installation and tried to fix it by re-installing without deleting the old installation, it would copy the broken settings and usually work even less than before.
Maybe GP still remembers that time and based his statement on that
I'm not so sure about newer versions, as I made a habit of doing always clean installs back then. Never tried to "repair-install" W2k or later.