The American (and not only American) penitential system is a disgrace and most probably often equals to gross violations of human rights.America has the highest incarceration rate in the world. Rape is so prevalent inside the prison system, it's become a "running joke" on network television. When's the last time you heard about 20 people being shot/killed in one weekend in Abu Dhabi or Saudi Arabia? It doesn't happen... it does however take place almost every weekend in the summer in Chicago/Baltimore. We sure do like to point our fingers at other countries though.....
At the same time, how do you know what really goes on in Saudi or UAE? It's not like they have free press that will publish trustworthy reports. We know that they publicly behead people in Saudi, often for victimless crimes, we know about the tortures, we know about the hypocrisy of the elites (that goes beyond even the ridiculously high levels of hypocrisy and corruption of the Western elites), we know about the armies of de facto slaves from South and Southeast Asia.
Yes, you are right that we should first look at the violations of freedom and human rights taking place in our own jurisdictions. However, I would still venture to say that people enjoy less freedom in the UAE and in this context it does not surprise me that their government chose to ban kava.