Most unions don't have "union" in their name, I don't think it's an issue of nomenclature. People know which organizations can be colloquially referred to as a labor union.

That said people just have problems understanding how unions work. It's a collective voice. How that voice is used is up to the union members. If you want that to include gate keeping and seniority protections that's up to the members. If you want it to be a political lobby, same thing.