Thank you, David, for your thoughts on debate.  My reply:

1. David adds a principle to my list:

Admit when you’re wrong. Or, even if the person on the other
side hasn’t convinced you that you’re wrong, but has made you have
doubts, admit that you have doubts.

I fully agree.

2. David’s other main observation: “Appeals to emotion can be sleazy, but they’re not necessarily sleazy.”

My initial reaction was to disagree, but David’s presentation gave me some doubts.  On third thought, though, I stand by my original claim. 

Key point: What counts as an “appeal to emotion”?  It can’t merely be any claim expected to produce a favorable emotion in the audience.  By that standard, after all, virtually every statement a debater bothers to make constitutes an appeal to emotion.  The standard meaning is much narrower.  As Wikipedia puts it:

Appeal to emotion or argumentum ad passiones is a logical fallacy characterized by the manipulation of the recipient’s emotions in order to win an argument, especially in the absence of factual evidence.

The “especially in the absence of factual evidence” clause is fundamental. 

Doesn’t my Haitian example still qualify?  As a moral realist who believes in moral facts, I say no.  The flip side, incidentally, is that if you’re a moral anti-realist, debating morality requires logical fallacy.  But that’s your problem!