Here in the United States we generally use the term "czar" to refer to the head of an executive branch official how has been appointed by the President. They serve at the leisure of the President with no oversight from the other branches of government.
We need to stop using the term because it's disrespectful to both the specific agency head and the agency. The title does not officially exist.
The term "czar" is inappropriate for all appointees. A czar stems from a monarchy and means emperor. In this day and age we have gotten past these types of leaderships. We have moved on to presidents and even now there is only one country that still uses the term King and Queen.
Yes, I strongly believe that we should immediately stop calling newly appointed public officials czars. I think that they should go by another name that does not remind everyone of the former USSR, and that the word "czar" carries with it such a strong connotation in every sense of the word.
These labels became popular during the Cold War. People assumed "czar" was a good word because Russia had previously been ruled by one and after that it was ruled by the Soviet Union which overthrew the czar. But the Czar was if anything worse than Lenin though not as bad as Stalin. He was a corrupt tyrant. While the Soviet Union turned out to be no improvement we shouldn't be casually using "czar" to refer to appointed officials as if "czar" was a positive thing.