Yes it is but I don't see why the part of Apples EULA saying you can't install MacOS on other hardware would be ruled unenforceable or invalid.
Even if that part is invalid, only people with actual Mac computers would be in the clear because that's the only way to get a copy of the OS. Apple won't sell it to you by itself. Anyone else making a hacintosh also has piracy issues to contend with.
It depends on whether you think Apples EULA is valid or not. It's never been ruled on by a court as far as I know.
The closest we got was the Psystar case which Apple won, so there is precedent that third parties can't install MacOS on a computer and sell it to you. I suppose it's also precedent that at least some of Apples EULA is enforceable.
Personally, I think that the EULA is valid and hackintoshes are a violation. Even so, it's unlikely that Apple will sue you for it.
