It is, in fact, just a joke. It comes from a time before the Thai subtree even, not long after the old forum, where the Thai subtree was heavily bashed by Chinese players. This was meant as a joking response to that situation from a Polish player.
It was approved because it’s still a well written suggestion on the Polish helicopters themselves, and the section on where a nation is placed in these types of suggestions is meaningless anyways.
This can still be a nice suggestion for a future Polish helicopter tree.