As a side note, this was also the pre-Google Internet era, with super early Linux (can't even remember the version). I remember using NCSA Mosaic!
On your Linux setup, could you do just fine without a mouse AND without a keyboard?
Why is it OK for the keyboard to be an essential required device but a mouse should be optional?
The key is flexiblity. On Linux, I could avoid my mouse or my keyboard or my entire graphical desktop if I wanted to and still be productive. Macs don't have that flexibility.
I single out a mouse because it is a very low information density device. It doesn't really do much, so it is the low hanging fruit. Whether a mouse is required by an OS is like a litmus test of "can the user configure the OS the way they want, or does the OS dictate how the user will use it"
Requiring a mouse and assuming it to always be present is not a bad thing; it's progress.
macOS has good accessibility features, so you can set it up to use it without a mouse if you really need to.