Hilchot Tefilah 10:5-6 (The Heretical (maybe) Chazan)

If a person refuses to lead the prayers because of a seemingly innocuous request – that he wants to wear only white clothing or pray without shoes – we ban him from serving as a chazan for this prayer, and, according to some authorities, permanently. What are we afraid of? What is the basis of the disagreement about whether the ban is temporary or permanent?