Libre software is about empowering users.
It's about the users having rights, instead of developers having rights.
This is fundamental and non-negotiable.
When you purposefully and deliberately shut out a significant portion of your community over your personal feelings, you are taking away the rights of your users.
Libre software developers should be dedicated to making adoption of libre software easier. Better user interfaces and experiences. Wider compatibility. That's how we all win.
X12 hypothetical was written by a completely different group, 3 years after Wayland started. The X12 spec deliberately calls out network transparency and framebuffer support as critical, while Wayland does away with network transparency ("no one cares" per the Wayland dev I spoke to) and virtually no compositors support fbdev.
I'd support what X12 wanted to be; Wayland falls short of that. Maybe with extensions. But then we're right back where we were with X11.