(un)reason
Legend
You could also make calling Aarakocra in your world "Wind Ducks" a derogatory term, like a slur.
Life is like a hurricane :slap bass intensifies:Your players' quote is the Secret Phrase that triggers genetic memory from ages long gone, and sends aarakocra into a frenzied rage. Nobody knows why (but some kind of magical curse is the go-to guess). They keep raging until every non-aarakocra is dead or has fled beyond line-of-sight.
(great, now I want to design a prestige class who's powers are entirely named after the lines in that song)