There is no invitation to join - you inherited the citizenship. You may not agree with where the money goes but its up to you to change the system. There isn't really a way to opt out/move away but that's the limit of the analogy rather than of the logic.
Isn't that the problem libertarians are trying to find a solution for? Is your agrument now "there are no libertarian places out there, you live in a Democratic government society, so just buck up and deal with it?"
No one said just deal with it. If you don't like it, change it. Currently, the vast majority of society has VOLUNTARILY decided that it does NOT want what you're selling, which brings us back to my question that no one wants to answer.
HOW do you plan on changing it without being a hypocrite at the same time?
So which is it? Are you going to bring about change by forcing it on people via violence (just like the state that you hate!) or are you going to win over a majority through superior reasoning and arguments (which will still result in your forcing your opinion on the minority, thus concluding that libertarianism is hypocritical and contradictory no matter what way you slice it, as I've said in a million threads before, you can't make EVERYONE happy ALL the time, thus you will ALWAYS have to suppress at least some people via threat of violence)?