Reading the thread, I'd say that's a mischaracterization of what happened: it appears that it was primarily a misunderstanding of the netbsd's development and the terminology used therein.
You have not read the thread, then. Because people made the point that wg(4) was not WireGuard, but an effectively clean-room implementation done by a NetBSD contributor based upon public doco. The WireGuard person made the point that wg(4) was not WireGuard, had had no involvement from WireGuard, and was incomplete or even faulty in some way. (I've had a look around, and I cannot find Jason A. Donenfeld coming back later in the intervening years to explain what the vague "halfbaked code"'s problems were. Of course, it's a lot more difficult to search mailing list archives than it used to be. But xe definitely did not come back the next week as promised, at least publically.) There was even a side-discussion about removing mention of the name to make it clear that it wasn't WireGuard.