Coincidentally, the source for this list is also wikipedia. The exclusion from the list has probably something to do with: Niue "a self-governing state in free association with New Zealand; and New Zealand conducts most diplomatic relations (though not all) on its behalf. Niueans are citizens of New Zealand" and somewhat similar case with Cook Islands, however, they have been taking more steps towards independence lately. So, we'll see how it goes with them. If these two were included, there'd be many others to add to the list for the same grounds e.g. Greenland.
The countries on the list, as I understand, demand a recognition of full independence including their own nationality, foreign policy, defence etc.
Palau, Federated States of Micronesia, and the Marshall Islands are all in free association with the United States and continue to be fully recognized as sovereign states. Although, Cook Islands and Niue do not strive to be considered independent, being in free association has never really matter on whether or not a state is sovereign or not.
I'm sorry if it sounded like I disagreed with them not being included, I was just making sure that it wasn't because they were in free association with New Zealand.
No worries. In running a tourism site, people keep on sending death threats for mentioning a location or not mentioning one. You're just hardballin' for information. Good that things are clear now.
The countries on the list, as I understand, demand a recognition of full independence including their own nationality, foreign policy, defence etc.
"The criteria for inclusion means a polity must claim sovereignty, lack recognition from at least one UN member state, and either:
satisfy the declarative theory of statehood, or
be recognised as a state by at least one UN member state."
Hope this helps you.