…in other words “Haiku operating system”, and in short “Haiku”, and in this context “Haiku” and “Haiku” are synonymous: they designate one and the same thing. (Also I should add that creating homonym it is a bad policy for the language. And this project did this. And this brings some bad consequences.)
…and they take “haiku-os.org” domain showing us that that is the next best thing to “haiku.org”.
…also fact is that nothing wrong in saying or writing “Haiku”
“Haiku” is technically correct when speaking about our operating system.
“Haiku OS” is not really correct. “The Haiku operating system” would technically be better.
“Go” is technically correct when speaking about the programming language.
“Go-lang” isn’t really correct, but is helpful to identify what you’re talking about when you’re not around programmers. (or googling funny enough)
Running through the Go forums and IRC shouting “Go-lang” will likely get you some odd looks from the Go developers.
It’s all our fault for having “haiku-os.org” because we really didn’t want to blow the huge sum of cash for haiku.org