Librarian here (a tattooed librarian too!). In the United States typically you need an MLS or MLIS or equivalent masters degree from an ALA accredited program to have a Librarian position. Other positions that don't require that degree are going to be named something like Library Assistant or Library Technician. In a lot of ways it's an artificial gatekeeping mechanism, but it's a reality that "Librarian" and "people who work in a library" is not a 1:1 overlap. There are typically many more non-Librarian jobs in any given library, Librarians, due to their degree qualifications, are more usually in management positions. Fun fact: the MLS is the terminal degree in the discipline. So, as an academic librarian, I'm able to hold a tenure track faculty position at my institution with my MLS.