Thanks ... yeah, that appears to be the case. The CFAX_WinTest software talks to the parallel port through a special driver on one of the standard hardware parallel-port addresses, which even a low-level USB-to-IEEE1284 adapter (if one exists) wouldn't match. Of course, since the source code is provided, one could probably tweak the software to work with such a low-level adapter (if one exists), but out-of-the-box, it looks like the demo board/software combination only works with a real, old-fashioned parallel port.
I dusted off one of my old computers that still had a parallel port and was able to get the demo board/software up and running successfully on that. I have some questions about the LCD itself now, which I'll ask in a new thread.
By the way the CFAXZIF-DEMO product page links to the wrong software. It links to
https://www.crystalfontz.com/software/CFAX_WinTest/; it should link to
https://www.crystalfontz.com/product/CFAX_WinTest.