I don't avoid "debate" because I fear disagreement or attacks. I avoid "debate" because so often when I enter one, the person engaging with me immediately employs ad hominem attacks or strawmen or appeals to emotions or any number of other unconstructive argumentation techniques. I am tired of engaging people who cannot argue using logic or rationality. I avoid it because it will be tedius and draining and there is no hope against someone not using logic. (Obviously this whole statement is merely an anecdote, and I'm not trying to explain trends.)