I believe civility is important. When you have laid it out in your syllabus, sent out an email with Course Policies and Procedures, reminded them in their Tips for Success each week, what else can you do?
You can set an example, even for the angriest student, by keeping your cool and replying in a slow and steady voice...you are setting an example for the netiquette and civility you expect.
I believe that the instructor often sets the tone for the class. What kind of tone are you setting for yours?
