If you take people who feel so strongly against libertarianism, the country won't remain libertarian for long. Of course, it means the person is charge is shaping his society, which is non-libertarian, but it's a sort of trade off.
There's nothing to say that a communist or a nazi is going to do anything to take down Liberland. Isn't excluding someone for their beliefs a thought-crime kind of situation?
I see no possible way kicking people out for thinking stuff is compatible with libertarian freedom-based ideas. Do they break libertarian law? Exile them. Do they talk about breaking libertarian law, or changing the laws there to reflect what they want? On what basis can you exclude someone for talking?
Nonsense. A pure voluntaryist country would be a great place to start a commune. You'd just need some seed capital to buy the land, and then you could live in a moneyless society free from wage-labor and other capitalist practices.
It will not last, as kibbutzes (examples of such communes) did not last in Israel. Ayn Rand has illustrated why in her book "Atlas Shrugged" with the example of Starnesville.
The reason is that people who are doing better than others (and who are forced by the communist _ideology_ to share so that everyone is equal), would leave the commune.
That is why North Korea and USSR kept their citizens inside the Iron Wall border. It "worked" only by forcing the able to their knees.
I see what you're trying to say, but at this point in history there is not a lot of intersection between "advocate for commune living" and "communist." Politics is an odd thing.
From their website: Liberland will accept anyone of any background as long they are not Communists, Nazis or other types of extremists.