Earlier quoted context omitted.
I was about to call that the Rundfunkbeitrag is not legally a tax (Steuer), but a tax (Beitrag). For some reason that difference does not seem to exist in English and it translates to the same word??
Tax vs contribution?
When I think of "Contributions" I think of a voluntary transfer of money, whether from an individual to an organization or from an individual to themselves (like "contributions" to an IRA or 401k for example). But a contribution could even be sharing ideas with a group of friends (contributing to the conversation) or anything really.