That's because in the US we don't give non-state organization power over other people. At least not in the European way where you have to give your life to an org. A US citizen has the freedom to disassociate with any organization at any time for any reason.

Of course this comes with a social cost, offset as this allows people who are discontent with their arrangements to forge a new path States like California have high job lock, so most innovation comes from side-projects as people checkout from work.