The tribalism quote reminds me of the 8-bit computer "wars" of the 1980's. Home computers were new, and there were so many different brands. Commodore 64, Apple 2, Atari 800, Texas Instruments, Sinclair, Radio Shack. There were very few standards, so each system had it's own chipset, languages, software, even data storage formats were different. There were RS232 serial and centronics port standards, but usually a company had their own type of connector, with their own printers, modems, cartridges, etc.
If you spent the money to buy a home computer system, then you had an "investment" in that technology. You kinda became an advocate by default, because if the users didn't promote their chosen brand, the company could fold. Without the company there'd be no new software developed for it, compatible peripherals would no longer be available, you might not even be able to get ribbons for your unique printer.
Computing tribalism was a form of competition.