To the extent that the aversion does nothing but increase the rumination and suffering, how is it rational?
People in a state of suffering or distress clearly are irrational... that's practically what the term means.
You're ascribing some negative value to the word, for some reason. Judgements themselves are usually irrational.
Rationality is an ideal, more or less. Animals are fundamentally irrational, and humans are definitely animals...
Are you saying suffering from pain is irrational? I'm not sure I follow your train of thought.