Q:

How to protest when a moderator deletes an answer?

Moderators have privileges that other users do not have. It not seem fair to all moderators be from one sect. maybe it is better moderators be from both Shia and Sunni Muslims. 
Anyway I do not see any option for appeal when a Question or Answer is completely deleted by an admin.

A:

To answer your question, if you can no longer post on the question or answer itself, you can make a post on meta. One post, not three posts. It helps to post with an open mind and try to understand their reasoning rather than attack their intentions from the outset. Then you can make your case and let them decide whether to keep it closed/deleted or reopen/undelete it.

