Does it, though?
"My way or the highway" fits very well in this context. "My way or the highway" can also be interpreted as "we don't give a single shit about other software and other people, and we don't care about interoperating with them".
Basically GNOME is living in and pushing a world where there's only GNOME.
And this is where things get tricky and I feel for the supposed "haters": so now you (GNOME) are a big project and you're pushing your own incompatible and non-interoperable stuff. Some projects will adhere, some won't, for any reason.
So now if I'm using anything not GNOME my desktop experience is broken, because software that assume GNOME is running won't work well (if at all) in other environments.
It just wasn't this bad before GNOME3 and this mentality shift.
No, that's false. I can't see why you'd even think that. GNOME wouldn't be using Wayland at all if that were true. GNOME uses standards where they make sense, this one optional non-standard part of Wayland just happens to not make any sense for GNOME. They don't have any issue with the rest of Wayland.
That's a false dilemma. You don't have to do either of those. The alternate solution is mentioned in that issue: use libdecor. I'll also note, if you refuse to use any of the system's UI and you insist on implement everything yourself directly on libwayland then that's an entirely self-inflicted problem that you created. Libwayland is fairly low-level, it isn't a game development API. Besides window decorations, you'll have lots of other deficiencies and things you have to spend development time on. That's what you volunteered for, GNOME can't help you with that.
Its pretty annoying to add another moving piece to the machinery just to do that.