A man cannot be compelled to self-incriminate
Sure they can. Do this field sobriety/breathalyzer/blood test combo. Oh, you refuse? Don't worry, we'll use that as evidence against you in a criminal case because you broke a civil law!
It is not different here. They are nailing the dude for contempt, not for not testifying against himself. There are always ways around that bush
the court may not presume guilt (innocent until proven guilty), and the court can only establish guilt through due process of law (everything from investigation to conviction)
I'd like to also point out this isn't the only scenario where your "constitutional rights" are subverted by twisted perversion of the law